Changeset 11543
- Timestamp:
- 2019-09-13T15:57:52+02:00 (4 years ago)
- Location:
- NEMO/trunk/doc/latex
- Files:
-
- 19 edited
- 7 moved
Legend:
- Unmodified
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NEMO/trunk/doc/latex/NEMO/main/appendices.tex
r11330 r11543 1 1 2 \subfile{../subfiles/a nnex_A}%% Generalised vertical coordinate3 \subfile{../subfiles/a nnex_B} %% Diffusive operator4 \subfile{../subfiles/a nnex_C}%% Discrete invariants of the eqs.5 \subfile{../subfiles/a nnex_iso}%% Isoneutral diffusion using triads6 \subfile{../subfiles/a nnex_DOMAINcfg}%% Brief notes on DOMAINcfg2 \subfile{../subfiles/apdx_s_coord} %% Generalised vertical coordinate 3 \subfile{../subfiles/apdx_diff_opers} %% Diffusive operators 4 \subfile{../subfiles/apdx_invariants} %% Discrete invariants of the eqs. 5 \subfile{../subfiles/apdx_triads} %% Isoneutral diffusion using triads 6 \subfile{../subfiles/apdx_DOMAINcfg} %% Brief notes on DOMAINcfg 7 7 8 8 %% Not included … … 10 10 %\subfile{../subfiles/chap_DIU} 11 11 %\subfile{../subfiles/chap_conservation} 12 %\subfile{../subfiles/annex_E} %% Notes on some on going staff 13 12 %\subfile{../subfiles/apdx_algos} %% Notes on some on going staff -
NEMO/trunk/doc/latex/NEMO/main/chapters.tex
r11522 r11543 13 13 \subfile{../subfiles/chap_STO} %% Stochastic param. 14 14 \subfile{../subfiles/chap_misc} %% Miscellaneous topics 15 \subfile{../subfiles/chap_ CONFIG}%% Predefined configurations15 \subfile{../subfiles/chap_cfgs} %% Predefined configurations 16 16 17 17 %% Not included -
NEMO/trunk/doc/latex/NEMO/main/introduction.tex
r11522 r11543 56 56 57 57 \begin{description} 58 \item [\nameref{chap: PE}] presents the equations and their assumptions, the vertical coordinates used,58 \item [\nameref{chap:MB}] presents the equations and their assumptions, the vertical coordinates used, 59 59 and the subgrid scale physics. 60 60 The equations are written in a curvilinear coordinate system, with a choice of vertical coordinates … … 63 63 Dimensional units in the meter, kilogram, second (MKS) international system are used throughout. 64 64 The following chapters deal with the discrete equations. 65 \item [\nameref{chap: STP}] presents the model time stepping environment.65 \item [\nameref{chap:TD}] presents the model time stepping environment. 66 66 it is a three level scheme in which the tendency terms of the equations are evaluated either 67 67 centered in time, or forward, or backward depending of the nature of the term. … … 123 123 \item [\nameref{chap:ASM}] describes how increments produced by 124 124 data \textbf{A}s\textbf{S}i\textbf{M}ilation may be applied to the model equations. 125 \item [\nameref{chap:STO}] 125 126 \item [\nameref{chap:MISC}] (including solvers) 126 \item [\nameref{chap:CFG }] provides finally a brief introduction to127 \item [\nameref{chap:CFGS}] provides finally a brief introduction to 127 128 the pre-defined model configurations 128 129 (water column model \texttt{C1D}, ORCA and GYRE families of configurations). … … 133 134 134 135 \begin{description} 135 \item [\nameref{apdx: s_coord}]136 \item [\nameref{apdx: diff_oper}]137 \item [\nameref{apdx: invariants}]138 \item [\nameref{apdx: triads}]139 \item [\nameref{apdx:DOM AINcfg}]140 \item [\nameref{apdx: coding}]136 \item [\nameref{apdx:SCOORD}] 137 \item [\nameref{apdx:DIFFOPERS}] 138 \item [\nameref{apdx:INVARIANTS}] 139 \item [\nameref{apdx:TRIADS}] 140 \item [\nameref{apdx:DOMCFG}] 141 \item [\nameref{apdx:CODING}] 141 142 \end{description} -
NEMO/trunk/doc/latex/NEMO/subfiles/apdx_DOMAINcfg.tex
r11529 r11543 6 6 % ================================================================ 7 7 \chapter{A brief guide to the DOMAINcfg tool} 8 \label{apdx:DOM AINcfg}8 \label{apdx:DOMCFG} 9 9 10 10 \chaptertoc … … 121 121 The reference coordinate transformation $z_0(k)$ defines the arrays $gdept_0$ and 122 122 $gdepw_0$ for $t$- and $w$-points, respectively. See \autoref{sec:DOMCFG_sco} for the 123 S-coordinate options. As indicated on \autoref{fig: index_vert} \jp{jpk} is the number of123 S-coordinate options. As indicated on \autoref{fig:DOM_index_vert} \jp{jpk} is the number of 124 124 $w$-levels. $gdepw_0(1)$ is the ocean surface. There are at most \jp{jpk}-1 $t$-points 125 125 inside the ocean, the additional $t$-point at $jk = jpk$ is below the sea floor and is not … … 421 421 The depth field $h$ is not necessary the ocean depth, 422 422 since a mixed step-like and bottom-following representation of the topography can be used 423 (\autoref{fig: z_zps_s_sps}) or an envelop bathymetry can be defined (\autoref{fig:z_zps_s_sps}).423 (\autoref{fig:DOM_z_zps_s_sps}) or an envelop bathymetry can be defined (\autoref{fig:DOM_z_zps_s_sps}). 424 424 The namelist parameter \np{rn\_rmax} determines the slope at which 425 425 the terrain-following coordinate intersects the sea bed and becomes a pseudo z-coordinate. … … 436 436 \[ 437 437 z = s_{min} + C (s) (H - s_{min}) 438 % \label{eq: SH94_1}438 % \label{eq:DOMCFG_SH94_1} 439 439 \] 440 440 … … 458 458 + b \frac{\tanh \lt[ \theta \lt(s + \frac{1}{2} \rt) \rt] - \tanh \lt( \frac{\theta}{2} \rt)} 459 459 { 2 \tanh \lt( \frac{\theta}{2} \rt)} 460 \label{eq: SH94_2}460 \label{eq:DOMCFG_SH94_2} 461 461 \] 462 462 … … 466 466 \includegraphics[width=\textwidth]{Fig_sco_function} 467 467 \caption{ 468 \protect\label{fig: sco_function}468 \protect\label{fig:DOMCFG_sco_function} 469 469 Examples of the stretching function applied to a seamount; 470 470 from left to right: surface, surface and bottom, and bottom intensified resolutions … … 478 478 bottom control parameters such that $0 \leqslant \theta \leqslant 20$, and $0 \leqslant b \leqslant 1$. 479 479 $b$ has been designed to allow surface and/or bottom increase of the vertical resolution 480 (\autoref{fig: sco_function}).480 (\autoref{fig:DOMCFG_sco_function}). 481 481 482 482 Another example has been provided at version 3.5 (\np{ln\_s\_SF12}) that allows a fixed surface resolution in … … 486 486 \begin{equation} 487 487 z = - \gamma h \quad \text{with} \quad 0 \leq \gamma \leq 1 488 % \label{eq: z}488 % \label{eq:DOMCFG_z} 489 489 \end{equation} 490 490 … … 524 524 For clarity every third coordinate surface is shown. 525 525 } 526 \label{fig: fig_compare_coordinates_surface}526 \label{fig:DOMCFG_fig_compare_coordinates_surface} 527 527 \end{figure} 528 528 % >>>>>>>>>>>>>>>>>>>>>>>>>>>> -
NEMO/trunk/doc/latex/NEMO/subfiles/apdx_algos.tex
r11529 r11543 6 6 % ================================================================ 7 7 \chapter{Note on some algorithms} 8 \label{apdx: E}8 \label{apdx:ALGOS} 9 9 10 10 \chaptertoc … … 12 12 \newpage 13 13 14 This appendix some on going consideration on algorithms used or planned to be used in \NEMO. 14 This appendix some on going consideration on algorithms used or planned to be used in \NEMO. 15 15 16 16 % ------------------------------------------------------------------------------------------------------------- 17 % UBS scheme 17 % UBS scheme 18 18 % ------------------------------------------------------------------------------------------------------------- 19 19 \section{Upstream Biased Scheme (UBS) (\protect\np{ln\_traadv\_ubs}\forcode{ = .true.})} … … 45 45 a constant i-grid spacing ($\Delta i=1$). 46 46 47 Alternative choice: introduce the scale factors: 47 Alternative choice: introduce the scale factors: 48 48 $\tau "_i =\frac{e_{1T}}{e_{2T}\,e_{3T}}\delta_i \left[ \frac{e_{2u} e_{3u} }{e_{1u} }\delta_{i+1/2}[\tau] \right]$. 49 49 … … 54 54 It is not a \emph{positive} scheme meaning false extrema are permitted but 55 55 the amplitude of such are significantly reduced over the centred second order method. 56 Nevertheless it is not recommended to apply it to a passive tracer that requires positivity. 56 Nevertheless it is not recommended to apply it to a passive tracer that requires positivity. 57 57 58 58 The intrinsic diffusion of UBS makes its use risky in the vertical direction where … … 61 61 \np{ln\_traadv\_ubs}\forcode{ = .true.}. 62 62 63 For stability reasons, in \autoref{eq: tra_adv_ubs}, the first term which corresponds to63 For stability reasons, in \autoref{eq:TRA_adv_ubs}, the first term which corresponds to 64 64 a second order centred scheme is evaluated using the \textit{now} velocity (centred in time) while 65 65 the second term which is the diffusive part of the scheme, is evaluated using the \textit{before} velocity … … 67 67 This is discussed by \citet{webb.de-cuevas.ea_JAOT98} in the context of the Quick advection scheme. 68 68 UBS and QUICK schemes only differ by one coefficient. 69 Substituting 1/6 with 1/8 in (\autoref{eq: tra_adv_ubs}) leads to the QUICK advection scheme \citep{webb.de-cuevas.ea_JAOT98}.69 Substituting 1/6 with 1/8 in (\autoref{eq:TRA_adv_ubs}) leads to the QUICK advection scheme \citep{webb.de-cuevas.ea_JAOT98}. 70 70 This option is not available through a namelist parameter, since the 1/6 coefficient is hard coded. 71 71 Nevertheless it is quite easy to make the substitution in \mdl{traadv\_ubs} module and obtain a QUICK scheme. … … 75 75 Computer time can be saved by using a time-splitting technique on vertical advection. 76 76 This possibility have been implemented and validated in ORCA05-L301. 77 It is not currently offered in the current reference version. 77 It is not currently offered in the current reference version. 78 78 79 79 NB 2: In a forthcoming release four options will be proposed for the vertical component used in the UBS scheme. … … 83 83 The $3^{rd}$ case has dispersion properties similar to an eight-order accurate conventional scheme. 84 84 85 NB 3: It is straight forward to rewrite \autoref{eq: tra_adv_ubs} as follows:85 NB 3: It is straight forward to rewrite \autoref{eq:TRA_adv_ubs} as follows: 86 86 \begin{equation} 87 87 \label{eq:tra_adv_ubs2} … … 93 93 \right. 94 94 \end{equation} 95 or equivalently 95 or equivalently 96 96 \begin{equation} 97 97 \label{eq:tra_adv_ubs2} … … 102 102 \end{split} 103 103 \end{equation} 104 \autoref{eq: tra_adv_ubs2} has several advantages.104 \autoref{eq:TRA_adv_ubs2} has several advantages. 105 105 First it clearly evidences that the UBS scheme is based on the fourth order scheme to which 106 106 is added an upstream biased diffusive term. 107 107 Second, this emphasises that the $4^{th}$ order part have to be evaluated at \emph{now} time step, 108 not only the $2^{th}$ order part as stated above using \autoref{eq: tra_adv_ubs}.108 not only the $2^{th}$ order part as stated above using \autoref{eq:TRA_adv_ubs}. 109 109 Third, the diffusive term is in fact a biharmonic operator with a eddy coefficient which 110 110 is simply proportional to the velocity. … … 134 134 \end{split} 135 135 \end{equation} 136 with ${A_u^{lT}}^2 = \frac{1}{12} {e_{1u}}^3\ |u|$, 136 with ${A_u^{lT}}^2 = \frac{1}{12} {e_{1u}}^3\ |u|$, 137 137 \ie\ $A_u^{lT} = \frac{1}{\sqrt{12}} \,e_{1u}\ \sqrt{ e_{1u}\,|u|\,}$ 138 138 it comes: … … 189 189 190 190 % ------------------------------------------------------------------------------------------------------------- 191 % Leap-Frog energetic 191 % Leap-Frog energetic 192 192 % ------------------------------------------------------------------------------------------------------------- 193 193 \section{Leapfrog energetic} … … 214 214 \equiv \frac{1}{\rdt} \overline{ \delta_{t+\rdt/2}[q]}^{\,t} 215 215 = \frac{q^{t+\rdt}-q^{t-\rdt}}{2\rdt} 216 \] 216 \] 217 217 Note that \autoref{chap:LF} shows that the leapfrog time step is $\rdt$, 218 218 not $2\rdt$ as it can be found sometimes in literature. … … 226 226 \] 227 227 is satisfied in discrete form. 228 Indeed, 228 Indeed, 229 229 \[ 230 230 \begin{split} … … 240 240 \] 241 241 NB here pb of boundary condition when applying the adjoint! 242 In space, setting to 0 the quantity in land area is sufficient to get rid of the boundary condition 242 In space, setting to 0 the quantity in land area is sufficient to get rid of the boundary condition 243 243 (equivalently of the boundary value of the integration by part). 244 244 In time this boundary condition is not physical and \textbf{add something here!!!} 245 245 246 246 % ================================================================ 247 % Iso-neutral diffusion : 247 % Iso-neutral diffusion : 248 248 % ================================================================ 249 249 … … 251 251 252 252 % ================================================================ 253 % Griffies' iso-neutral diffusion operator : 253 % Griffies' iso-neutral diffusion operator : 254 254 % ================================================================ 255 255 \subsection{Griffies iso-neutral diffusion operator} … … 258 258 but is formulated within the \NEMO\ framework 259 259 (\ie\ using scale factors rather than grid-size and having a position of $T$-points that 260 is not necessary in the middle of vertical velocity points, see \autoref{fig: zgr_e3}).261 262 In the formulation \autoref{eq: tra_ldf_iso} introduced in 1995 in OPA, the ancestor of \NEMO,260 is not necessary in the middle of vertical velocity points, see \autoref{fig:DOM_zgr_e3}). 261 262 In the formulation \autoref{eq:TRA_ldf_iso} introduced in 1995 in OPA, the ancestor of \NEMO, 263 263 the off-diagonal terms of the small angle diffusion tensor contain several double spatial averages of a gradient, 264 264 for example $\overline{\overline{\delta_k \cdot}}^{\,i,k}$. … … 318 318 %>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> 319 319 320 The four iso-neutral fluxes associated with the triads are defined at $T$-point. 320 The four iso-neutral fluxes associated with the triads are defined at $T$-point. 321 321 They take the following expression: 322 322 \begin{flalign*} … … 332 332 333 333 The resulting iso-neutral fluxes at $u$- and $w$-points are then given by 334 the sum of the fluxes that cross the $u$- and $w$-face (\autoref{fig: ISO_triad}):334 the sum of the fluxes that cross the $u$- and $w$-face (\autoref{fig:TRIADS_ISO_triad}): 335 335 \begin{flalign} 336 336 \label{eq:iso_flux} … … 369 369 + \delta_{k} \left[ {_i^{k+1/2-k_p} {\mathbb{F}_w}_{i_p}^{k_p}} \right] \right\} 370 370 \end{equation} 371 where $b_T= e_{1T}\,e_{2T}\,e_{3T}$ is the volume of $T$-cells. 371 where $b_T= e_{1T}\,e_{2T}\,e_{3T}$ is the volume of $T$-cells. 372 372 373 373 This expression of the iso-neutral diffusion has been chosen in order to satisfy the following six properties: … … 448 448 449 449 % ================================================================ 450 % Skew flux formulation for Eddy Induced Velocity : 450 % Skew flux formulation for Eddy Induced Velocity : 451 451 % ================================================================ 452 452 \subsection{Eddy induced velocity and skew flux formulation} … … 457 457 the formulation of which depends on the slopes of iso-neutral surfaces. 458 458 Contrary to the case of iso-neutral mixing, the slopes used here are referenced to the geopotential surfaces, 459 \ie\ \autoref{eq: ldfslp_geo} is used in $z$-coordinate,460 and the sum \autoref{eq: ldfslp_geo} + \autoref{eq:ldfslp_iso} in $z^*$ or $s$-coordinates.461 462 The eddy induced velocity is given by: 459 \ie\ \autoref{eq:LDF_slp_geo} is used in $z$-coordinate, 460 and the sum \autoref{eq:LDF_slp_geo} + \autoref{eq:LDF_slp_iso} in $z^*$ or $s$-coordinates. 461 462 The eddy induced velocity is given by: 463 463 \begin{equation} 464 464 \label{eq:eiv_v} … … 484 484 (see \autoref{sec:TRA_adv}) and not just a $2^{nd}$ order advection scheme. 485 485 This is particularly useful for passive tracers where 486 \emph{positivity} of the advection scheme is of paramount importance. 487 % give here the expression using the triads. It is different from the one given in \autoref{eq: ldfeiv}486 \emph{positivity} of the advection scheme is of paramount importance. 487 % give here the expression using the triads. It is different from the one given in \autoref{eq:LDF_eiv} 488 488 % see just below a copy of this equation: 489 489 %\begin{equation} \label{eq:ldfeiv} … … 593 593 \right) 594 594 \end{equation} 595 Note that \autoref{eq:eiv_skew} is valid in $z$-coordinate with or without partial cells. 595 Note that \autoref{eq:eiv_skew} is valid in $z$-coordinate with or without partial cells. 596 596 In $z^*$ or $s$-coordinate, the slope between the level and the geopotential surfaces must be added to 597 $\mathbb{R}$ for the discret form to be exact. 597 $\mathbb{R}$ for the discret form to be exact. 598 598 599 599 Such a choice of discretisation is consistent with the iso-neutral operator as … … 604 604 $\ $\newpage %force an empty line 605 605 % ================================================================ 606 % Discrete Invariants of the iso-neutral diffrusion 606 % Discrete Invariants of the iso-neutral diffrusion 607 607 % ================================================================ 608 608 \subsection{Discrete invariants of the iso-neutral diffrusion} 609 609 \label{subsec:Gf_operator} 610 610 611 Demonstration of the decrease of the tracer variance in the (\textbf{i},\textbf{j}) plane. 611 Demonstration of the decrease of the tracer variance in the (\textbf{i},\textbf{j}) plane. 612 612 613 613 This part will be moved in an Appendix. … … 617 617 \int_D D_l^T \; T \;dv \leq 0 618 618 \] 619 The discrete form of its left hand side is obtained using \autoref{eq: iso_flux}619 The discrete form of its left hand side is obtained using \autoref{eq:TRIADS_iso_flux} 620 620 621 621 \begin{align*} … … 740 740 \right\} 741 741 \quad \leq 0 742 \end{align*} 742 \end{align*} 743 743 The last inequality is obviously obtained as we succeed in obtaining a negative summation of square quantities. 744 744 … … 764 764 % 765 765 &\equiv \sum_{i,k} \left\{ D_l^S \ T \ b_T \right\} 766 \end{align*} 766 \end{align*} 767 767 This means that the iso-neutral operator is self-adjoint. 768 768 There is no need to develop a specific to obtain it. … … 776 776 \label{subsec:eiv_skew} 777 777 778 Demonstration for the conservation of the tracer variance in the (\textbf{i},\textbf{j}) plane. 778 Demonstration for the conservation of the tracer variance in the (\textbf{i},\textbf{j}) plane. 779 779 780 780 This have to be moved in an Appendix. … … 830 830 &{\ \ \;_i^k \mathbb{R}_{+1/2}^{+1/2}} &\delta_{i+1/2}[T^{k\ \ \ \:}] &\delta_{k+1/2}[T_{i}] 831 831 &\Bigr\} \\ 832 \end{matrix} 832 \end{matrix} 833 833 \end{align*} 834 834 The two terms associated with the triad ${_i^k \mathbb{R}_{+1/2}^{+1/2}}$ are the same but of opposite signs, 835 they cancel out. 835 they cancel out. 836 836 Exactly the same thing occurs for the triad ${_i^k \mathbb{R}_{-1/2}^{-1/2}}$. 837 837 The two terms associated with the triad ${_i^k \mathbb{R}_{+1/2}^{-1/2}}$ are the same but both of opposite signs and -
NEMO/trunk/doc/latex/NEMO/subfiles/apdx_diff_opers.tex
r11529 r11543 5 5 % Chapter Appendix B : Diffusive Operators 6 6 % ================================================================ 7 \chapter{ Appendix B :Diffusive Operators}8 \label{apdx: B}7 \chapter{Diffusive Operators} 8 \label{apdx:DIFFOPERS} 9 9 10 10 \chaptertoc … … 16 16 % ================================================================ 17 17 \section{Horizontal/Vertical $2^{nd}$ order tracer diffusive operators} 18 \label{sec: B_1}18 \label{sec:DIFFOPERS_1} 19 19 20 20 \subsubsection*{In z-coordinates} … … 22 22 In $z$-coordinates, the horizontal/vertical second order tracer diffusion operator is given by: 23 23 \begin{align} 24 \label{ apdx:B1}24 \label{eq:DIFFOPERS_1} 25 25 &D^T = \frac{1}{e_1 \, e_2} \left[ 26 26 \left. \frac{\partial}{\partial i} \left( \frac{e_2}{e_1}A^{lT} \;\left. \frac{\partial T}{\partial i} \right|_z \right) \right|_z \right. … … 32 32 \subsubsection*{In generalized vertical coordinates} 33 33 34 In $s$-coordinates, we defined the slopes of $s$-surfaces, $\sigma_1$ and $\sigma_2$ by \autoref{ apdx:A_s_slope} and34 In $s$-coordinates, we defined the slopes of $s$-surfaces, $\sigma_1$ and $\sigma_2$ by \autoref{eq:SCOORD_s_slope} and 35 35 the vertical/horizontal ratio of diffusion coefficient by $\epsilon = A^{vT} / A^{lT}$. 36 36 The diffusion operator is given by: 37 37 38 38 \begin{equation} 39 \label{ apdx:B2}39 \label{eq:DIFFOPERS_2} 40 40 D^T = \left. \nabla \right|_s \cdot 41 41 \left[ A^{lT} \;\Re \cdot \left. \nabla \right|_s T \right] \\ … … 54 54 \begin{array}{*{20}l} 55 55 D^T= \frac{1}{e_1\,e_2\,e_3 } & \left\{ \quad \quad \frac{\partial }{\partial i} \left. \left[ e_2\,e_3 \, A^{lT} 56 \left( \ \frac{1}{e_1}\; \left. \frac{\partial T}{\partial i} \right|_s 56 \left( \ \frac{1}{e_1}\; \left. \frac{\partial T}{\partial i} \right|_s 57 57 -\frac{\sigma_1 }{e_3 } \; \frac{\partial T}{\partial s} \right) \right] \right|_s \right. \\ 58 58 & \quad \ + \ \left. \frac{\partial }{\partial j} \left. \left[ e_1\,e_3 \, A^{lT} 59 \left( \ \frac{1}{e_2 }\; \left. \frac{\partial T}{\partial j} \right|_s 59 \left( \ \frac{1}{e_2 }\; \left. \frac{\partial T}{\partial j} \right|_s 60 60 -\frac{\sigma_2 }{e_3 } \; \frac{\partial T}{\partial s} \right) \right] \right|_s \right. \\ 61 & \quad \ + \ \left. e_1\,e_2\, \frac{\partial }{\partial s} \left[ A^{lT} \; \left( 62 -\frac{\sigma_1 }{e_1 } \; \left. \frac{\partial T}{\partial i} \right|_s 63 -\frac{\sigma_2 }{e_2 } \; \left. \frac{\partial T}{\partial j} \right|_s 61 & \quad \ + \ \left. e_1\,e_2\, \frac{\partial }{\partial s} \left[ A^{lT} \; \left( 62 -\frac{\sigma_1 }{e_1 } \; \left. \frac{\partial T}{\partial i} \right|_s 63 -\frac{\sigma_2 }{e_2 } \; \left. \frac{\partial T}{\partial j} \right|_s 64 64 +\left( \varepsilon +\sigma_1^2+\sigma_2 ^2 \right) \; \frac{1}{e_3 } \; \frac{\partial T}{\partial s} \right) \; \right] \; \right\} . 65 65 \end{array} … … 67 67 \end{align*} 68 68 69 \autoref{ apdx:B2} is obtained from \autoref{apdx:B1} without any additional assumption.69 \autoref{eq:DIFFOPERS_2} is obtained from \autoref{eq:DIFFOPERS_1} without any additional assumption. 70 70 Indeed, for the special case $k=z$ and thus $e_3 =1$, 71 we introduce an arbitrary vertical coordinate $s = s (i,j,z)$ as in \autoref{apdx: A} and72 use \autoref{ apdx:A_s_slope} and \autoref{apdx:A_s_chain_rule}.73 Since no cross horizontal derivative $\partial _i \partial _j $ appears in \autoref{ apdx:B1},71 we introduce an arbitrary vertical coordinate $s = s (i,j,z)$ as in \autoref{apdx:SCOORD} and 72 use \autoref{eq:SCOORD_s_slope} and \autoref{eq:SCOORD_s_chain_rule}. 73 Since no cross horizontal derivative $\partial _i \partial _j $ appears in \autoref{eq:DIFFOPERS_1}, 74 74 the ($i$,$z$) and ($j$,$z$) planes are independent. 75 75 The derivation can then be demonstrated for the ($i$,$z$)~$\to$~($j$,$s$) transformation without … … 160 160 % ================================================================ 161 161 \section{Iso/Diapycnal $2^{nd}$ order tracer diffusive operators} 162 \label{sec: B_2}162 \label{sec:DIFFOPERS_2} 163 163 164 164 \subsubsection*{In z-coordinates} … … 170 170 171 171 \begin{equation} 172 \label{ apdx:B3}172 \label{eq:DIFFOPERS_3} 173 173 \textbf {A}_{\textbf I} = \frac{A^{lT}}{\left( {1+a_1 ^2+a_2 ^2} \right)} 174 174 \left[ {{ … … 193 193 194 194 In practice, $\epsilon$ is small and isopycnal slopes are generally less than $10^{-2}$ in the ocean, 195 so $\textbf {A}_{\textbf I}$ can be simplified appreciably \citep{cox_OM87}. Keeping leading order terms\footnote{Apart from the (1,0) 195 so $\textbf {A}_{\textbf I}$ can be simplified appreciably \citep{cox_OM87}. Keeping leading order terms\footnote{Apart from the (1,0) 196 196 and (0,1) elements which are set to zero. See \citet{griffies_bk04}, section 14.1.4.1 for a discussion of this point.}: 197 197 \begin{subequations} 198 \label{ apdx:B4}198 \label{eq:DIFFOPERS_4} 199 199 \begin{equation} 200 \label{ apdx:B4a}200 \label{eq:DIFFOPERS_4a} 201 201 {\textbf{A}_{\textbf{I}}} \approx A^{lT}\;\Re\;\text{where} \;\Re = 202 202 \left[ {{ … … 210 210 and the iso/dianeutral diffusive operator in $z$-coordinates is then 211 211 \begin{equation} 212 \label{ apdx:B4b}212 \label{eq:DIFFOPERS_4b} 213 213 D^T = \left. \nabla \right|_z \cdot 214 214 \left[ A^{lT} \;\Re \cdot \left. \nabla \right|_z T \right]. \\ … … 216 216 \end{subequations} 217 217 218 Physically, the full tensor \autoref{ apdx:B3} represents strong isoneutral diffusion on a plane parallel to218 Physically, the full tensor \autoref{eq:DIFFOPERS_3} represents strong isoneutral diffusion on a plane parallel to 219 219 the isoneutral surface and weak dianeutral diffusion perpendicular to this plane. 220 220 However, 221 the approximate `weak-slope' tensor \autoref{ apdx:B4a} represents strong diffusion along the isoneutral surface,221 the approximate `weak-slope' tensor \autoref{eq:DIFFOPERS_4a} represents strong diffusion along the isoneutral surface, 222 222 with weak \emph{vertical} diffusion -- the principal axes of the tensor are no longer orthogonal. 223 223 This simplification also decouples the ($i$,$z$) and ($j$,$z$) planes of the tensor. 224 The weak-slope operator therefore takes the same form, \autoref{ apdx:B4}, as \autoref{apdx:B2},224 The weak-slope operator therefore takes the same form, \autoref{eq:DIFFOPERS_4}, as \autoref{eq:DIFFOPERS_2}, 225 225 the diffusion operator for geopotential diffusion written in non-orthogonal $i,j,s$-coordinates. 226 226 Written out explicitly, 227 227 228 228 \begin{multline} 229 \label{ apdx:B_ldfiso}229 \label{eq:DIFFOPERS_ldfiso} 230 230 D^T=\frac{1}{e_1 e_2 }\left\{ 231 231 {\;\frac{\partial }{\partial i}\left[ {A_h \left( {\frac{e_2}{e_1}\frac{\partial T}{\partial i}-a_1 \frac{e_2}{e_3}\frac{\partial T}{\partial k}} \right)} \right]} … … 234 234 \end{multline} 235 235 236 The isopycnal diffusion operator \autoref{ apdx:B4},237 \autoref{ apdx:B_ldfiso} conserves tracer quantity and dissipates its square.238 As \autoref{ apdx:B4} is the divergence of a flux, the demonstration of the first property is trivial, providing that the flux normal to the boundary is zero236 The isopycnal diffusion operator \autoref{eq:DIFFOPERS_4}, 237 \autoref{eq:DIFFOPERS_ldfiso} conserves tracer quantity and dissipates its square. 238 As \autoref{eq:DIFFOPERS_4} is the divergence of a flux, the demonstration of the first property is trivial, providing that the flux normal to the boundary is zero 239 239 (as it is when $A_h$ is zero at the boundary). Let us demonstrate the second one: 240 240 \[ … … 256 256 j}-a_2 \frac{\partial T}{\partial k}} \right)^2} 257 257 +\varepsilon \left(\frac{\partial T}{\partial k}\right) ^2\right] \\ 258 & \geq 0 . 258 & \geq 0 . 259 259 \end{array} 260 260 } … … 265 265 \subsubsection*{In generalized vertical coordinates} 266 266 267 Because the weak-slope operator \autoref{ apdx:B4},268 \autoref{ apdx:B_ldfiso} is decoupled in the ($i$,$z$) and ($j$,$z$) planes,267 Because the weak-slope operator \autoref{eq:DIFFOPERS_4}, 268 \autoref{eq:DIFFOPERS_ldfiso} is decoupled in the ($i$,$z$) and ($j$,$z$) planes, 269 269 it may be transformed into generalized $s$-coordinates in the same way as 270 \autoref{sec: B_1} was transformed into \autoref{sec:B_2}.270 \autoref{sec:DIFFOPERS_1} was transformed into \autoref{sec:DIFFOPERS_2}. 271 271 The resulting operator then takes the simple form 272 272 273 273 \begin{equation} 274 \label{ apdx:B_ldfiso_s}274 \label{eq:DIFFOPERS_ldfiso_s} 275 275 D^T = \left. \nabla \right|_s \cdot 276 276 \left[ A^{lT} \;\Re \cdot \left. \nabla \right|_s T \right] \\ … … 295 295 \] 296 296 297 To prove \autoref{ apdx:B_ldfiso_s} by direct re-expression of \autoref{apdx:B_ldfiso} is straightforward, but laborious.298 An easier way is first to note (by reversing the derivation of \autoref{sec: B_2} from \autoref{sec:B_1} ) that297 To prove \autoref{eq:DIFFOPERS_ldfiso_s} by direct re-expression of \autoref{eq:DIFFOPERS_ldfiso} is straightforward, but laborious. 298 An easier way is first to note (by reversing the derivation of \autoref{sec:DIFFOPERS_2} from \autoref{sec:DIFFOPERS_1} ) that 299 299 the weak-slope operator may be \emph{exactly} reexpressed in non-orthogonal $i,j,\rho$-coordinates as 300 300 301 301 \begin{equation} 302 \label{ apdx:B5}302 \label{eq:DIFFOPERS_5} 303 303 D^T = \left. \nabla \right|_\rho \cdot 304 304 \left[ A^{lT} \;\Re \cdot \left. \nabla \right|_\rho T \right] \\ … … 312 312 \end{equation} 313 313 Then direct transformation from $i,j,\rho$-coordinates to $i,j,s$-coordinates gives 314 \autoref{ apdx:B_ldfiso_s} immediately.314 \autoref{eq:DIFFOPERS_ldfiso_s} immediately. 315 315 316 316 Note that the weak-slope approximation is only made in transforming from … … 318 318 The further transformation into $i,j,s$-coordinates is exact, whatever the steepness of the $s$-surfaces, 319 319 in the same way as the transformation of horizontal/vertical Laplacian diffusion in $z$-coordinates in 320 \autoref{sec: B_1} onto $s$-coordinates is exact, however steep the $s$-surfaces.320 \autoref{sec:DIFFOPERS_1} onto $s$-coordinates is exact, however steep the $s$-surfaces. 321 321 322 322 … … 325 325 % ================================================================ 326 326 \section{Lateral/Vertical momentum diffusive operators} 327 \label{sec: B_3}327 \label{sec:DIFFOPERS_3} 328 328 329 329 The second order momentum diffusion operator (Laplacian) in $z$-coordinates is found by 330 applying \autoref{eq: PE_lap_vector}, the expression for the Laplacian of a vector,330 applying \autoref{eq:MB_lap_vector}, the expression for the Laplacian of a vector, 331 331 to the horizontal velocity vector: 332 332 \begin{align*} … … 371 371 }} \right) 372 372 \end{align*} 373 Using \autoref{eq: PE_div}, the definition of the horizontal divergence,373 Using \autoref{eq:MB_div}, the definition of the horizontal divergence, 374 374 the third component of the second vector is obviously zero and thus : 375 375 \[ 376 \Delta {\textbf{U}}_h = \nabla _h \left( \chi \right) - \nabla _h \times \left( \zeta \textbf{k} \right) + \frac {1}{e_3 } \frac {\partial }{\partial k} \left( {\frac {1}{e_3 } \frac{\partial {\textbf{ U}}_h }{\partial k}} \right) . 376 \Delta {\textbf{U}}_h = \nabla _h \left( \chi \right) - \nabla _h \times \left( \zeta \textbf{k} \right) + \frac {1}{e_3 } \frac {\partial }{\partial k} \left( {\frac {1}{e_3 } \frac{\partial {\textbf{ U}}_h }{\partial k}} \right) . 377 377 \] 378 378 379 379 Note that this operator ensures a full separation between 380 the vorticity and horizontal divergence fields (see \autoref{apdx: C}).380 the vorticity and horizontal divergence fields (see \autoref{apdx:INVARIANTS}). 381 381 It is only equal to a Laplacian applied to each component in Cartesian coordinates, not on the sphere. 382 382 … … 384 384 the $z$-coordinate therefore takes the following form: 385 385 \begin{equation} 386 \label{ apdx:B_Lap_U}386 \label{eq:DIFFOPERS_Lap_U} 387 387 { 388 388 \textbf{D}}^{\textbf{U}} = … … 404 404 \end{align*} 405 405 406 Note Bene: introducing a rotation in \autoref{ apdx:B_Lap_U} does not lead to406 Note Bene: introducing a rotation in \autoref{eq:DIFFOPERS_Lap_U} does not lead to 407 407 a useful expression for the iso/diapycnal Laplacian operator in the $z$-coordinate. 408 408 Similarly, we did not found an expression of practical use for 409 409 the geopotential horizontal/vertical Laplacian operator in the $s$-coordinate. 410 Generally, \autoref{ apdx:B_Lap_U} is used in both $z$- and $s$-coordinate systems,410 Generally, \autoref{eq:DIFFOPERS_Lap_U} is used in both $z$- and $s$-coordinate systems, 411 411 that is a Laplacian diffusion is applied on momentum along the coordinate directions. 412 412 -
NEMO/trunk/doc/latex/NEMO/subfiles/apdx_invariants.tex
r11529 r11543 6 6 % ================================================================ 7 7 \chapter{Discrete Invariants of the Equations} 8 \label{apdx: C}8 \label{apdx:INVARIANTS} 9 9 10 10 \chaptertoc … … 21 21 % ================================================================ 22 22 \section{Introduction / Notations} 23 \label{sec: C.0}23 \label{sec:INVARIANTS_0} 24 24 25 25 Notation used in this appendix in the demonstations: … … 72 72 that is in a more compact form : 73 73 \begin{flalign} 74 \label{eq: Q2_flux}74 \label{eq:INVARIANTS_Q2_flux} 75 75 \partial_t \left( \int_D {\frac{1}{2} Q^2\;dv} \right) 76 76 =& \int_D { \frac{Q}{e_3} \partial_t \left( e_3 \, Q \right) dv } … … 87 87 that is in a more compact form: 88 88 \begin{flalign} 89 \label{eq: Q2_vect}89 \label{eq:INVARIANTS_Q2_vect} 90 90 \partial_t \left( \int_D {\frac{1}{2} Q^2\;dv} \right) 91 91 =& \int_D { Q \,\partial_t Q \;dv } … … 97 97 % ================================================================ 98 98 \section{Continuous conservation} 99 \label{sec: C.1}99 \label{sec:INVARIANTS_1} 100 100 101 101 The discretization of pimitive equation in $s$-coordinate (\ie\ time and space varying vertical coordinate) … … 105 105 The total energy (\ie\ kinetic plus potential energies) is conserved: 106 106 \begin{flalign} 107 \label{eq: Tot_Energy}107 \label{eq:INVARIANTS_Tot_Energy} 108 108 \partial_t \left( \int_D \left( \frac{1}{2} {\textbf{U}_h}^2 + \rho \, g \, z \right) \;dv \right) = & 0 109 109 \end{flalign} … … 114 114 The transformation for the advection term depends on whether the vector invariant form or 115 115 the flux form is used for the momentum equation. 116 Using \autoref{eq: Q2_vect} and introducing \autoref{apdx:A_dyn_vect} in117 \autoref{eq: Tot_Energy} for the former form and118 using \autoref{eq: Q2_flux} and introducing \autoref{apdx:A_dyn_flux} in119 \autoref{eq: Tot_Energy} for the latter form leads to:120 121 % \label{eq: E_tot}116 Using \autoref{eq:INVARIANTS_Q2_vect} and introducing \autoref{eq:SCOORD_dyn_vect} in 117 \autoref{eq:INVARIANTS_Tot_Energy} for the former form and 118 using \autoref{eq:INVARIANTS_Q2_flux} and introducing \autoref{eq:SCOORD_dyn_flux} in 119 \autoref{eq:INVARIANTS_Tot_Energy} for the latter form leads to: 120 121 % \label{eq:INVARIANTS_E_tot} 122 122 advection term (vector invariant form): 123 123 \[ 124 % \label{eq: E_tot_vect_vor_1}124 % \label{eq:INVARIANTS_E_tot_vect_vor_1} 125 125 \int\limits_D \zeta \; \left( \textbf{k} \times \textbf{U}_h \right) \cdot \textbf{U}_h \; dv = 0 \\ 126 126 \] 127 127 % 128 128 \[ 129 % \label{eq: E_tot_vect_adv_1}129 % \label{eq:INVARIANTS_E_tot_vect_adv_1} 130 130 \int\limits_D \textbf{U}_h \cdot \nabla_h \left( \frac{{\textbf{U}_h}^2}{2} \right) dv 131 131 + \int\limits_D \textbf{U}_h \cdot \nabla_z \textbf{U}_h \;dv … … 134 134 advection term (flux form): 135 135 \[ 136 % \label{eq: E_tot_flux_metric}136 % \label{eq:INVARIANTS_E_tot_flux_metric} 137 137 \int\limits_D \frac{1} {e_1 e_2 } \left( v \,\partial_i e_2 - u \,\partial_j e_1 \right)\; 138 138 \left( \textbf{k} \times \textbf{U}_h \right) \cdot \textbf{U}_h \; dv = 0 139 139 \] 140 140 \[ 141 % \label{eq: E_tot_flux_adv}141 % \label{eq:INVARIANTS_E_tot_flux_adv} 142 142 \int\limits_D \textbf{U}_h \cdot \left( {{ 143 143 \begin{array} {*{20}c} … … 150 150 coriolis term 151 151 \[ 152 % \label{eq: E_tot_cor}152 % \label{eq:INVARIANTS_E_tot_cor} 153 153 \int\limits_D f \; \left( \textbf{k} \times \textbf{U}_h \right) \cdot \textbf{U}_h \; dv = 0 154 154 \] 155 155 pressure gradient: 156 156 \[ 157 % \label{eq: E_tot_pg_1}157 % \label{eq:INVARIANTS_E_tot_pg_1} 158 158 - \int\limits_D \left. \nabla p \right|_z \cdot \textbf{U}_h \;dv 159 159 = - \int\limits_D \nabla \cdot \left( \rho \,\textbf {U} \right)\;g\;z\;\;dv … … 173 173 174 174 Vector invariant form: 175 % \label{eq: E_tot_vect}176 \[ 177 % \label{eq: E_tot_vect_vor_2}175 % \label{eq:INVARIANTS_E_tot_vect} 176 \[ 177 % \label{eq:INVARIANTS_E_tot_vect_vor_2} 178 178 \int\limits_D \textbf{U}_h \cdot \text{VOR} \;dv = 0 179 179 \] 180 180 \[ 181 % \label{eq: E_tot_vect_adv_2}181 % \label{eq:INVARIANTS_E_tot_vect_adv_2} 182 182 \int\limits_D \textbf{U}_h \cdot \text{KEG} \;dv 183 183 + \int\limits_D \textbf{U}_h \cdot \text{ZAD} \;dv … … 185 185 \] 186 186 \[ 187 % \label{eq: E_tot_pg_2}187 % \label{eq:INVARIANTS_E_tot_pg_2} 188 188 - \int\limits_D \textbf{U}_h \cdot (\text{HPG}+ \text{SPG}) \;dv 189 189 = - \int\limits_D \nabla \cdot \left( \rho \,\textbf {U} \right)\;g\;z\;\;dv … … 193 193 Flux form: 194 194 \begin{subequations} 195 \label{eq: E_tot_flux}195 \label{eq:INVARIANTS_E_tot_flux} 196 196 \[ 197 % \label{eq: E_tot_flux_metric_2}197 % \label{eq:INVARIANTS_E_tot_flux_metric_2} 198 198 \int\limits_D \textbf{U}_h \cdot \text {COR} \; dv = 0 199 199 \] 200 200 \[ 201 % \label{eq: E_tot_flux_adv_2}201 % \label{eq:INVARIANTS_E_tot_flux_adv_2} 202 202 \int\limits_D \textbf{U}_h \cdot \text{ADV} \;dv 203 203 + \frac{1}{2} \int\limits_D { {\textbf{U}_h}^2 \frac{1}{e_3} \partial_t e_3 \;dv } =\;0 204 204 \] 205 205 \begin{equation} 206 \label{eq: E_tot_pg_3}206 \label{eq:INVARIANTS_E_tot_pg_3} 207 207 - \int\limits_D \textbf{U}_h \cdot (\text{HPG}+ \text{SPG}) \;dv 208 208 = - \int\limits_D \nabla \cdot \left( \rho \,\textbf {U} \right)\;g\;z\;\;dv … … 211 211 \end{subequations} 212 212 213 \autoref{eq: E_tot_pg_3} is the balance between the conversion KE to PE and PE to KE.214 Indeed the left hand side of \autoref{eq: E_tot_pg_3} can be transformed as follows:213 \autoref{eq:INVARIANTS_E_tot_pg_3} is the balance between the conversion KE to PE and PE to KE. 214 Indeed the left hand side of \autoref{eq:INVARIANTS_E_tot_pg_3} can be transformed as follows: 215 215 \begin{flalign*} 216 216 \partial_t \left( \int\limits_D { \rho \, g \, z \;dv} \right) … … 225 225 \end{flalign*} 226 226 where the last equality is obtained by noting that the brackets is exactly the expression of $w$, 227 the vertical velocity referenced to the fixe $z$-coordinate system (see \autoref{ apdx:A_w_s}).228 229 The left hand side of \autoref{eq: E_tot_pg_3} can be transformed as follows:227 the vertical velocity referenced to the fixe $z$-coordinate system (see \autoref{eq:SCOORD_w_s}). 228 229 The left hand side of \autoref{eq:INVARIANTS_E_tot_pg_3} can be transformed as follows: 230 230 \begin{flalign*} 231 231 - \int\limits_D \left. \nabla p \right|_z & \cdot \textbf{U}_h \;dv … … 326 326 % ================================================================ 327 327 \section{Discrete total energy conservation: vector invariant form} 328 \label{sec: C.2}328 \label{sec:INVARIANTS_2} 329 329 330 330 % ------------------------------------------------------------------------------------------------------------- … … 332 332 % ------------------------------------------------------------------------------------------------------------- 333 333 \subsection{Total energy conservation} 334 \label{subsec: C_KE+PE_vect}335 336 The discrete form of the total energy conservation, \autoref{eq: Tot_Energy}, is given by:334 \label{subsec:INVARIANTS_KE+PE_vect} 335 336 The discrete form of the total energy conservation, \autoref{eq:INVARIANTS_Tot_Energy}, is given by: 337 337 \begin{flalign*} 338 338 \partial_t \left( \sum\limits_{i,j,k} \biggl\{ \frac{u^2}{2} \,b_u + \frac{v^2}{2}\, b_v + \rho \, g \, z_t \,b_t \biggr\} \right) &=0 … … 340 340 which in vector invariant forms, it leads to: 341 341 \begin{equation} 342 \label{eq: KE+PE_vect_discrete}342 \label{eq:INVARIANTS_KE+PE_vect_discrete} 343 343 \begin{split} 344 344 \sum\limits_{i,j,k} \biggl\{ u\, \partial_t u \;b_u … … 352 352 353 353 Substituting the discrete expression of the time derivative of the velocity either in vector invariant, 354 leads to the discrete equivalent of the four equations \autoref{eq: E_tot_flux}.354 leads to the discrete equivalent of the four equations \autoref{eq:INVARIANTS_E_tot_flux}. 355 355 356 356 % ------------------------------------------------------------------------------------------------------------- … … 358 358 % ------------------------------------------------------------------------------------------------------------- 359 359 \subsection{Vorticity term (coriolis + vorticity part of the advection)} 360 \label{subsec: C_vor}360 \label{subsec:INVARIANTS_vor} 361 361 362 362 Let $q$, located at $f$-points, be either the relative ($q=\zeta / e_{3f}$), … … 367 367 % ------------------------------------------------------------------------------------------------------------- 368 368 \subsubsection{Vorticity term with ENE scheme (\protect\np{ln\_dynvor\_ene}\forcode{ = .true.})} 369 \label{subsec: C_vorENE}369 \label{subsec:INVARIANTS_vorENE} 370 370 371 371 For the ENE scheme, the two components of the vorticity term are given by: … … 407 407 % ------------------------------------------------------------------------------------------------------------- 408 408 \subsubsection{Vorticity term with EEN scheme (\protect\np{ln\_dynvor\_een}\forcode{ = .true.})} 409 \label{subsec: C_vorEEN_vect}409 \label{subsec:INVARIANTS_vorEEN_vect} 410 410 411 411 With the EEN scheme, the vorticity terms are represented as: 412 412 \begin{equation} 413 \ tag{\ref{eq:dynvor_een}}413 \label{eq:INVARIANTS_dynvor_een} 414 414 \left\{ { 415 415 \begin{aligned} … … 424 424 and the vorticity triads, ${^i_j}\mathbb{Q}^{i_p}_{j_p}$, defined at $T$-point, are given by: 425 425 \begin{equation} 426 \ tag{\ref{eq:Q_triads}}426 \label{eq:INVARIANTS_Q_triads} 427 427 _i^j \mathbb{Q}^{i_p}_{j_p} 428 428 = \frac{1}{12} \ \left( q^{i-i_p}_{j+j_p} + q^{i+j_p}_{j+i_p} + q^{i+i_p}_{j-j_p} \right) … … 479 479 % ------------------------------------------------------------------------------------------------------------- 480 480 \subsubsection{Gradient of kinetic energy / Vertical advection} 481 \label{subsec: C_zad}481 \label{subsec:INVARIANTS_zad} 482 482 483 483 The change of Kinetic Energy (KE) due to the vertical advection is exactly balanced by the change of KE due to the horizontal gradient of KE~: … … 542 542 % 543 543 \intertext{The first term provides the discrete expression for the vertical advection of momentum (ZAD), 544 while the second term corresponds exactly to \autoref{eq: KE+PE_vect_discrete}, therefore:}544 while the second term corresponds exactly to \autoref{eq:INVARIANTS_KE+PE_vect_discrete}, therefore:} 545 545 \equiv& \int\limits_D \textbf{U}_h \cdot \text{ZAD} \;dv 546 546 + \frac{1}{2} \int_D { {\textbf{U}_h}^2 \frac{1}{e_3} \partial_t (e_3) \;dv } &&&\\ … … 578 578 which is (over-)satified by defining the vertical scale factor as follows: 579 579 \begin{flalign*} 580 % \label{eq: e3u-e3v}580 % \label{eq:INVARIANTS_e3u-e3v} 581 581 e_{3u} = \frac{1}{e_{1u}\,e_{2u}}\;\overline{ e_{1t}^{ }\,e_{2t}^{ }\,e_{3t}^{ } }^{\,i+1/2} \\ 582 582 e_{3v} = \frac{1}{e_{1v}\,e_{2v}}\;\overline{ e_{1t}^{ }\,e_{2t}^{ }\,e_{3t}^{ } }^{\,j+1/2} … … 590 590 % ------------------------------------------------------------------------------------------------------------- 591 591 \subsection{Pressure gradient term} 592 \label{subsec: C.2.6}592 \label{subsec:INVARIANTS_2.6} 593 593 594 594 \gmcomment{ … … 622 622 \allowdisplaybreaks 623 623 \intertext{Using successively \autoref{eq:DOM_di_adj}, \ie\ the skew symmetry property of 624 the $\delta$ operator, \autoref{eq: wzv}, the continuity equation, \autoref{eq:dynhpg_sco},624 the $\delta$ operator, \autoref{eq:DYN_wzv}, the continuity equation, \autoref{eq:DYN_hpg_sco}, 625 625 the hydrostatic equation in the $s$-coordinate, and $\delta_{k+1/2} \left[ z_t \right] \equiv e_{3w} $, 626 626 which comes from the definition of $z_t$, it becomes: } … … 667 667 % 668 668 \end{flalign*} 669 The first term is exactly the first term of the right-hand-side of \autoref{eq: KE+PE_vect_discrete}.669 The first term is exactly the first term of the right-hand-side of \autoref{eq:INVARIANTS_KE+PE_vect_discrete}. 670 670 It remains to demonstrate that the last term, 671 671 which is obviously a discrete analogue of $\int_D \frac{p}{e_3} \partial_t (e_3)\;dv$ is equal to 672 the last term of \autoref{eq: KE+PE_vect_discrete}.672 the last term of \autoref{eq:INVARIANTS_KE+PE_vect_discrete}. 673 673 In other words, the following property must be satisfied: 674 674 \begin{flalign*} … … 735 735 % ================================================================ 736 736 \section{Discrete total energy conservation: flux form} 737 \label{sec: C.3}737 \label{sec:INVARIANTS_3} 738 738 739 739 % ------------------------------------------------------------------------------------------------------------- … … 741 741 % ------------------------------------------------------------------------------------------------------------- 742 742 \subsection{Total energy conservation} 743 \label{subsec: C_KE+PE_flux}744 745 The discrete form of the total energy conservation, \autoref{eq: Tot_Energy}, is given by:743 \label{subsec:INVARIANTS_KE+PE_flux} 744 745 The discrete form of the total energy conservation, \autoref{eq:INVARIANTS_Tot_Energy}, is given by: 746 746 \begin{flalign*} 747 747 \partial_t \left( \sum\limits_{i,j,k} \biggl\{ \frac{u^2}{2} \,b_u + \frac{v^2}{2}\, b_v + \rho \, g \, z_t \,b_t \biggr\} \right) &=0 \\ … … 765 765 % ------------------------------------------------------------------------------------------------------------- 766 766 \subsection{Coriolis and advection terms: flux form} 767 \label{subsec: C.3.2}767 \label{subsec:INVARIANTS_3.2} 768 768 769 769 % ------------------------------------------------------------------------------------------------------------- … … 771 771 % ------------------------------------------------------------------------------------------------------------- 772 772 \subsubsection{Coriolis plus ``metric'' term} 773 \label{subsec: C.3.3}773 \label{subsec:INVARIANTS_3.3} 774 774 775 775 In flux from the vorticity term reduces to a Coriolis term in which … … 786 786 Either the ENE or EEN scheme is then applied to obtain the vorticity term in flux form. 787 787 It therefore conserves the total KE. 788 The derivation is the same as for the vorticity term in the vector invariant form (\autoref{subsec: C_vor}).788 The derivation is the same as for the vorticity term in the vector invariant form (\autoref{subsec:INVARIANTS_vor}). 789 789 790 790 % ------------------------------------------------------------------------------------------------------------- … … 792 792 % ------------------------------------------------------------------------------------------------------------- 793 793 \subsubsection{Flux form advection} 794 \label{subsec: C.3.4}794 \label{subsec:INVARIANTS_3.4} 795 795 796 796 The flux form operator of the momentum advection is evaluated using … … 800 800 801 801 \begin{equation} 802 \label{eq: C_ADV_KE_flux}802 \label{eq:INVARIANTS_ADV_KE_flux} 803 803 - \int_D \textbf{U}_h \cdot \left( {{ 804 804 \begin{array} {*{20}c} … … 863 863 \] 864 864 which is the discrete form of $ \frac{1}{2} \int_D u \cdot \nabla \cdot \left( \textbf{U}\,u \right) \; dv $. 865 \autoref{eq: C_ADV_KE_flux} is thus satisfied.865 \autoref{eq:INVARIANTS_ADV_KE_flux} is thus satisfied. 866 866 867 867 When the UBS scheme is used to evaluate the flux form momentum advection, … … 873 873 % ================================================================ 874 874 \section{Discrete enstrophy conservation} 875 \label{sec: C.4}875 \label{sec:INVARIANTS_4} 876 876 877 877 % ------------------------------------------------------------------------------------------------------------- … … 879 879 % ------------------------------------------------------------------------------------------------------------- 880 880 \subsubsection{Vorticity term with ENS scheme (\protect\np{ln\_dynvor\_ens}\forcode{ = .true.})} 881 \label{subsec: C_vorENS}881 \label{subsec:INVARIANTS_vorENS} 882 882 883 883 In the ENS scheme, the vorticity term is descretized as follows: 884 884 \begin{equation} 885 \ tag{\ref{eq:dynvor_ens}}885 \label{eq:INVARIANTS_dynvor_ens} 886 886 \left\{ 887 887 \begin{aligned} … … 898 898 it can be shown that: 899 899 \begin{equation} 900 \label{eq: C_1.1}900 \label{eq:INVARIANTS_1.1} 901 901 \int_D {q\,\;{\textbf{k}}\cdot \frac{1} {e_3} \nabla \times \left( {e_3 \, q \;{\textbf{k}}\times {\textbf{U}}_h } \right)\;dv} \equiv 0 902 902 \end{equation} 903 903 where $dv=e_1\,e_2\,e_3 \; di\,dj\,dk$ is the volume element. 904 Indeed, using \autoref{eq: dynvor_ens},905 the discrete form of the right hand side of \autoref{eq: C_1.1} can be transformed as follow:904 Indeed, using \autoref{eq:DYN_vor_ens}, 905 the discrete form of the right hand side of \autoref{eq:INVARIANTS_1.1} can be transformed as follow: 906 906 \begin{flalign*} 907 907 &\int_D q \,\; \textbf{k} \cdot \frac{1} {e_3 } \nabla \times … … 948 948 % ------------------------------------------------------------------------------------------------------------- 949 949 \subsubsection{Vorticity Term with EEN scheme (\protect\np{ln\_dynvor\_een}\forcode{ = .true.})} 950 \label{subsec: C_vorEEN}950 \label{subsec:INVARIANTS_vorEEN} 951 951 952 952 With the EEN scheme, the vorticity terms are represented as: 953 953 \begin{equation} 954 \ tag{\ref{eq:dynvor_een}}954 \label{eq:INVARIANTS_dynvor_een} 955 955 \left\{ { 956 956 \begin{aligned} … … 966 966 and the vorticity triads, ${^i_j}\mathbb{Q}^{i_p}_{j_p}$, defined at $T$-point, are given by: 967 967 \begin{equation} 968 \tag{\ref{eq: Q_triads}}968 \tag{\ref{eq:INVARIANTS_Q_triads}} 969 969 _i^j \mathbb{Q}^{i_p}_{j_p} 970 970 = \frac{1}{12} \ \left( q^{i-i_p}_{j+j_p} + q^{i+j_p}_{j+i_p} + q^{i+i_p}_{j-j_p} \right) … … 975 975 Let consider one of the vorticity triad, for example ${^{i}_j}\mathbb{Q}^{+1/2}_{+1/2} $, 976 976 similar manipulation can be done for the 3 others. 977 The discrete form of the right hand side of \autoref{eq: C_1.1} applied to977 The discrete form of the right hand side of \autoref{eq:INVARIANTS_1.1} applied to 978 978 this triad only can be transformed as follow: 979 979 … … 1021 1021 % ================================================================ 1022 1022 \section{Conservation properties on tracers} 1023 \label{sec: C.5}1023 \label{sec:INVARIANTS_5} 1024 1024 1025 1025 All the numerical schemes used in \NEMO\ are written such that the tracer content is conserved by … … 1037 1037 % ------------------------------------------------------------------------------------------------------------- 1038 1038 \subsection{Advection term} 1039 \label{subsec: C.5.1}1039 \label{subsec:INVARIANTS_5.1} 1040 1040 1041 1041 conservation of a tracer, $T$: … … 1103 1103 % ================================================================ 1104 1104 \section{Conservation properties on lateral momentum physics} 1105 \label{sec: dynldf_properties}1105 \label{sec:INVARIANTS_dynldf_properties} 1106 1106 1107 1107 The discrete formulation of the horizontal diffusion of momentum ensures … … 1124 1124 % ------------------------------------------------------------------------------------------------------------- 1125 1125 \subsection{Conservation of potential vorticity} 1126 \label{subsec: C.6.1}1126 \label{subsec:INVARIANTS_6.1} 1127 1127 1128 1128 The lateral momentum diffusion term conserves the potential vorticity: … … 1158 1158 % ------------------------------------------------------------------------------------------------------------- 1159 1159 \subsection{Dissipation of horizontal kinetic energy} 1160 \label{subsec: C.6.2}1160 \label{subsec:INVARIANTS_6.2} 1161 1161 1162 1162 The lateral momentum diffusion term dissipates the horizontal kinetic energy: … … 1210 1210 % ------------------------------------------------------------------------------------------------------------- 1211 1211 \subsection{Dissipation of enstrophy} 1212 \label{subsec: C.6.3}1212 \label{subsec:INVARIANTS_6.3} 1213 1213 1214 1214 The lateral momentum diffusion term dissipates the enstrophy when the eddy coefficients are horizontally uniform: … … 1234 1234 % ------------------------------------------------------------------------------------------------------------- 1235 1235 \subsection{Conservation of horizontal divergence} 1236 \label{subsec: C.6.4}1236 \label{subsec:INVARIANTS_6.4} 1237 1237 1238 1238 When the horizontal divergence of the horizontal diffusion of momentum (discrete sense) is taken, … … 1261 1261 % ------------------------------------------------------------------------------------------------------------- 1262 1262 \subsection{Dissipation of horizontal divergence variance} 1263 \label{subsec: C.6.5}1263 \label{subsec:INVARIANTS_6.5} 1264 1264 1265 1265 \begin{flalign*} … … 1287 1287 % ================================================================ 1288 1288 \section{Conservation properties on vertical momentum physics} 1289 \label{sec: C.7}1289 \label{sec:INVARIANTS_7} 1290 1290 1291 1291 As for the lateral momentum physics, … … 1458 1458 % ================================================================ 1459 1459 \section{Conservation properties on tracer physics} 1460 \label{sec: C.8}1460 \label{sec:INVARIANTS_8} 1461 1461 1462 1462 The numerical schemes used for tracer subgridscale physics are written such that … … 1470 1470 % ------------------------------------------------------------------------------------------------------------- 1471 1471 \subsection{Conservation of tracers} 1472 \label{subsec: C.8.1}1472 \label{subsec:INVARIANTS_8.1} 1473 1473 1474 1474 constraint of conservation of tracers: … … 1503 1503 % ------------------------------------------------------------------------------------------------------------- 1504 1504 \subsection{Dissipation of tracer variance} 1505 \label{subsec: C.8.2}1505 \label{subsec:INVARIANTS_8.2} 1506 1506 1507 1507 constraint on the dissipation of tracer variance: -
NEMO/trunk/doc/latex/NEMO/subfiles/apdx_s_coord.tex
r11529 r11543 7 7 % ================================================================ 8 8 \chapter{Curvilinear $s-$Coordinate Equations} 9 \label{apdx: A}9 \label{apdx:SCOORD} 10 10 11 11 \chaptertoc … … 28 28 % ================================================================ 29 29 \section{Chain rule for $s-$coordinates} 30 \label{sec: A_chain}30 \label{sec:SCOORD_chain} 31 31 32 32 In order to establish the set of Primitive Equation in curvilinear $s$-coordinates 33 33 (\ie\ an orthogonal curvilinear coordinate in the horizontal and 34 34 an Arbitrary Lagrangian Eulerian (ALE) coordinate in the vertical), 35 we start from the set of equations established in \autoref{subsec: PE_zco_Eq} for35 we start from the set of equations established in \autoref{subsec:MB_zco_Eq} for 36 36 the special case $k = z$ and thus $e_3 = 1$, 37 37 and we introduce an arbitrary vertical coordinate $a = a(i,j,z,t)$. … … 39 39 the horizontal slope of $s-$surfaces by: 40 40 \begin{equation} 41 \label{ apdx:A_s_slope}41 \label{eq:SCOORD_s_slope} 42 42 \sigma_1 =\frac{1}{e_1 } \; \left. {\frac{\partial z}{\partial i}} \right|_s 43 43 \quad \text{and} \quad … … 46 46 47 47 The model fields (e.g. pressure $p$) can be viewed as functions of $(i,j,z,t)$ (e.g. $p(i,j,z,t)$) or as 48 functions of $(i,j,s,t)$ (e.g. $p(i,j,s,t)$). The symbol $\bullet$ will be used to represent any one of 49 these fields. Any ``infinitesimal'' change in $\bullet$ can be written in two forms: 50 \begin{equation} 51 \label{ apdx:A_s_infin_changes}48 functions of $(i,j,s,t)$ (e.g. $p(i,j,s,t)$). The symbol $\bullet$ will be used to represent any one of 49 these fields. Any ``infinitesimal'' change in $\bullet$ can be written in two forms: 50 \begin{equation} 51 \label{eq:SCOORD_s_infin_changes} 52 52 \begin{aligned} 53 & \delta \bullet = \delta i \left. \frac{ \partial \bullet }{\partial i} \right|_{j,s,t} 54 + \delta j \left. \frac{ \partial \bullet }{\partial i} \right|_{i,s,t} 55 + \delta s \left. \frac{ \partial \bullet }{\partial s} \right|_{i,j,t} 53 & \delta \bullet = \delta i \left. \frac{ \partial \bullet }{\partial i} \right|_{j,s,t} 54 + \delta j \left. \frac{ \partial \bullet }{\partial i} \right|_{i,s,t} 55 + \delta s \left. \frac{ \partial \bullet }{\partial s} \right|_{i,j,t} 56 56 + \delta t \left. \frac{ \partial \bullet }{\partial t} \right|_{i,j,s} , \\ 57 & \delta \bullet = \delta i \left. \frac{ \partial \bullet }{\partial i} \right|_{j,z,t} 58 + \delta j \left. \frac{ \partial \bullet }{\partial i} \right|_{i,z,t} 59 + \delta z \left. \frac{ \partial \bullet }{\partial z} \right|_{i,j,t} 57 & \delta \bullet = \delta i \left. \frac{ \partial \bullet }{\partial i} \right|_{j,z,t} 58 + \delta j \left. \frac{ \partial \bullet }{\partial i} \right|_{i,z,t} 59 + \delta z \left. \frac{ \partial \bullet }{\partial z} \right|_{i,j,t} 60 60 + \delta t \left. \frac{ \partial \bullet }{\partial t} \right|_{i,j,z} . 61 61 \end{aligned} … … 63 63 Using the first form and considering a change $\delta i$ with $j, z$ and $t$ held constant, shows that 64 64 \begin{equation} 65 \label{ apdx:A_s_chain_rule}65 \label{eq:SCOORD_s_chain_rule} 66 66 \left. {\frac{\partial \bullet }{\partial i}} \right|_{j,z,t} = 67 67 \left. {\frac{\partial \bullet }{\partial i}} \right|_{j,s,t} 68 + \left. {\frac{\partial s }{\partial i}} \right|_{j,z,t} \; 69 \left. {\frac{\partial \bullet }{\partial s}} \right|_{i,j,t} . 70 \end{equation} 71 The term $\left. \partial s / \partial i \right|_{j,z,t}$ can be related to the slope of constant $s$ surfaces, 72 (\autoref{ apdx:A_s_slope}), by applying the second of (\autoref{apdx:A_s_infin_changes}) with $\bullet$ set to68 + \left. {\frac{\partial s }{\partial i}} \right|_{j,z,t} \; 69 \left. {\frac{\partial \bullet }{\partial s}} \right|_{i,j,t} . 70 \end{equation} 71 The term $\left. \partial s / \partial i \right|_{j,z,t}$ can be related to the slope of constant $s$ surfaces, 72 (\autoref{eq:SCOORD_s_slope}), by applying the second of (\autoref{eq:SCOORD_s_infin_changes}) with $\bullet$ set to 73 73 $s$ and $j, t$ held constant 74 74 \begin{equation} 75 \label{ apdx:a_delta_s}76 \delta s|_{j,t} = 77 \delta i \left. \frac{ \partial s }{\partial i} \right|_{j,z,t} 75 \label{eq:SCOORD_delta_s} 76 \delta s|_{j,t} = 77 \delta i \left. \frac{ \partial s }{\partial i} \right|_{j,z,t} 78 78 + \delta z \left. \frac{ \partial s }{\partial z} \right|_{i,j,t} . 79 79 \end{equation} 80 80 Choosing to look at a direction in the $(i,z)$ plane in which $\delta s = 0$ and using 81 (\autoref{ apdx:A_s_slope}) we obtain82 \begin{equation} 83 \left. \frac{ \partial s }{\partial i} \right|_{j,z,t} = 81 (\autoref{eq:SCOORD_s_slope}) we obtain 82 \begin{equation} 83 \left. \frac{ \partial s }{\partial i} \right|_{j,z,t} = 84 84 - \left. \frac{ \partial z }{\partial i} \right|_{j,s,t} \; 85 85 \left. \frac{ \partial s }{\partial z} \right|_{i,j,t} 86 86 = - \frac{e_1 }{e_3 }\sigma_1 . 87 \label{ apdx:a_ds_di_z}88 \end{equation} 89 Another identity, similar in form to (\autoref{ apdx:a_ds_di_z}), can be derived90 by choosing $\bullet$ to be $s$ and using the second form of (\autoref{ apdx:A_s_infin_changes}) to consider87 \label{eq:SCOORD_ds_di_z} 88 \end{equation} 89 Another identity, similar in form to (\autoref{eq:SCOORD_ds_di_z}), can be derived 90 by choosing $\bullet$ to be $s$ and using the second form of (\autoref{eq:SCOORD_s_infin_changes}) to consider 91 91 changes in which $i , j$ and $s$ are constant. This shows that 92 92 \begin{equation} 93 \label{ apdx:A_w_in_s}94 w_s = \left. \frac{ \partial z }{\partial t} \right|_{i,j,s} = 93 \label{eq:SCOORD_w_in_s} 94 w_s = \left. \frac{ \partial z }{\partial t} \right|_{i,j,s} = 95 95 - \left. \frac{ \partial z }{\partial s} \right|_{i,j,t} 96 \left. \frac{ \partial s }{\partial t} \right|_{i,j,z} 97 = - e_3 \left. \frac{ \partial s }{\partial t} \right|_{i,j,z} . 98 \end{equation} 99 100 In what follows, for brevity, indication of the constancy of the $i, j$ and $t$ indices is 101 usually omitted. Using the arguments outlined above one can show that the chain rules needed to establish 96 \left. \frac{ \partial s }{\partial t} \right|_{i,j,z} 97 = - e_3 \left. \frac{ \partial s }{\partial t} \right|_{i,j,z} . 98 \end{equation} 99 100 In what follows, for brevity, indication of the constancy of the $i, j$ and $t$ indices is 101 usually omitted. Using the arguments outlined above one can show that the chain rules needed to establish 102 102 the model equations in the curvilinear $s-$coordinate system are: 103 103 \begin{equation} 104 \label{ apdx:A_s_chain_rule}104 \label{eq:SCOORD_s_chain_rule} 105 105 \begin{aligned} 106 106 &\left. {\frac{\partial \bullet }{\partial t}} \right|_z = 107 \left. {\frac{\partial \bullet }{\partial t}} \right|_s 107 \left. {\frac{\partial \bullet }{\partial t}} \right|_s 108 108 + \frac{\partial \bullet }{\partial s}\; \frac{\partial s}{\partial t} , \\ 109 109 &\left. {\frac{\partial \bullet }{\partial i}} \right|_z = 110 110 \left. {\frac{\partial \bullet }{\partial i}} \right|_s 111 111 +\frac{\partial \bullet }{\partial s}\; \frac{\partial s}{\partial i}= 112 \left. {\frac{\partial \bullet }{\partial i}} \right|_s 112 \left. {\frac{\partial \bullet }{\partial i}} \right|_s 113 113 -\frac{e_1 }{e_3 }\sigma_1 \frac{\partial \bullet }{\partial s} , \\ 114 114 &\left. {\frac{\partial \bullet }{\partial j}} \right|_z = 115 \left. {\frac{\partial \bullet }{\partial j}} \right|_s 115 \left. {\frac{\partial \bullet }{\partial j}} \right|_s 116 116 + \frac{\partial \bullet }{\partial s}\;\frac{\partial s}{\partial j}= 117 \left. {\frac{\partial \bullet }{\partial j}} \right|_s 117 \left. {\frac{\partial \bullet }{\partial j}} \right|_s 118 118 - \frac{e_2 }{e_3 }\sigma_2 \frac{\partial \bullet }{\partial s} , \\ 119 119 &\;\frac{\partial \bullet }{\partial z} \;\; = \frac{1}{e_3 }\frac{\partial \bullet }{\partial s} . … … 126 126 % ================================================================ 127 127 \section{Continuity equation in $s-$coordinates} 128 \label{sec: A_continuity}129 130 Using (\autoref{ apdx:A_s_chain_rule}) and128 \label{sec:SCOORD_continuity} 129 130 Using (\autoref{eq:SCOORD_s_chain_rule}) and 131 131 the fact that the horizontal scale factors $e_1$ and $e_2$ do not depend on the vertical coordinate, 132 132 the divergence of the velocity relative to the ($i$,$j$,$z$) coordinate system is transformed as follows in order to … … 189 189 \end{subequations} 190 190 191 Here, $w$ is the vertical velocity relative to the $z-$coordinate system. 192 Using the first form of (\autoref{ apdx:A_s_infin_changes})193 and the definitions (\autoref{ apdx:A_s_slope}) and (\autoref{apdx:A_w_in_s}) for $\sigma_1$, $\sigma_2$ and $w_s$,191 Here, $w$ is the vertical velocity relative to the $z-$coordinate system. 192 Using the first form of (\autoref{eq:SCOORD_s_infin_changes}) 193 and the definitions (\autoref{eq:SCOORD_s_slope}) and (\autoref{eq:SCOORD_w_in_s}) for $\sigma_1$, $\sigma_2$ and $w_s$, 194 194 one can show that the vertical velocity, $w_p$ of a point 195 moving with the horizontal velocity of the fluid along an $s$ surface is given by 196 \begin{equation} 197 \label{ apdx:A_w_p}195 moving with the horizontal velocity of the fluid along an $s$ surface is given by 196 \begin{equation} 197 \label{eq:SCOORD_w_p} 198 198 \begin{split} 199 199 w_p = & \left. \frac{ \partial z }{\partial t} \right|_s 200 + \frac{u}{e_1} \left. \frac{ \partial z }{\partial i} \right|_s 200 + \frac{u}{e_1} \left. \frac{ \partial z }{\partial i} \right|_s 201 201 + \frac{v}{e_2} \left. \frac{ \partial z }{\partial j} \right|_s \\ 202 202 = & w_s + u \sigma_1 + v \sigma_2 . 203 \end{split} 203 \end{split} 204 204 \end{equation} 205 205 The vertical velocity across this surface is denoted by 206 206 \begin{equation} 207 \label{ apdx:A_w_s}208 \omega = w - w_p = w - ( w_s + \sigma_1 \,u + \sigma_2 \,v ) . 209 \end{equation} 210 Hence 211 \begin{equation} 212 \frac{1}{e_3 } \frac{\partial}{\partial s} \left[ w - u\;\sigma_1 - v\;\sigma_2 \right] = 213 \frac{1}{e_3 } \frac{\partial}{\partial s} \left[ \omega + w_s \right] = 214 \frac{1}{e_3 } \left[ \frac{\partial \omega}{\partial s} 215 + \left. \frac{ \partial }{\partial t} \right|_s \frac{\partial z}{\partial s} \right] = 216 \frac{1}{e_3 } \frac{\partial \omega}{\partial s} + \frac{1}{e_3 } \left. \frac{ \partial e_3}{\partial t} . \right|_s 217 \end{equation} 218 219 Using (\autoref{ apdx:A_w_s}) in our expression for $\nabla \cdot {\mathrm {\mathbf U}}$ we obtain207 \label{eq:SCOORD_w_s} 208 \omega = w - w_p = w - ( w_s + \sigma_1 \,u + \sigma_2 \,v ) . 209 \end{equation} 210 Hence 211 \begin{equation} 212 \frac{1}{e_3 } \frac{\partial}{\partial s} \left[ w - u\;\sigma_1 - v\;\sigma_2 \right] = 213 \frac{1}{e_3 } \frac{\partial}{\partial s} \left[ \omega + w_s \right] = 214 \frac{1}{e_3 } \left[ \frac{\partial \omega}{\partial s} 215 + \left. \frac{ \partial }{\partial t} \right|_s \frac{\partial z}{\partial s} \right] = 216 \frac{1}{e_3 } \frac{\partial \omega}{\partial s} + \frac{1}{e_3 } \left. \frac{ \partial e_3}{\partial t} . \right|_s 217 \end{equation} 218 219 Using (\autoref{eq:SCOORD_w_s}) in our expression for $\nabla \cdot {\mathrm {\mathbf U}}$ we obtain 220 220 our final expression for the divergence of the velocity in the curvilinear $s-$coordinate system: 221 221 \begin{equation} … … 228 228 \end{equation} 229 229 230 As a result, the continuity equation \autoref{eq: PE_continuity} in the $s-$coordinates is:231 \begin{equation} 232 \label{ apdx:A_sco_Continuity}230 As a result, the continuity equation \autoref{eq:MB_PE_continuity} in the $s-$coordinates is: 231 \begin{equation} 232 \label{eq:SCOORD_sco_Continuity} 233 233 \frac{1}{e_3 } \frac{\partial e_3}{\partial t} 234 234 + \frac{1}{e_1 \,e_2 \,e_3 }\left[ … … 245 245 % ================================================================ 246 246 \section{Momentum equation in $s-$coordinate} 247 \label{sec: A_momentum}247 \label{sec:SCOORD_momentum} 248 248 249 249 Here we only consider the first component of the momentum equation, … … 252 252 $\bullet$ \textbf{Total derivative in vector invariant form} 253 253 254 Let us consider \autoref{eq: PE_dyn_vect}, the first component of the momentum equation in the vector invariant form.254 Let us consider \autoref{eq:MB_dyn_vect}, the first component of the momentum equation in the vector invariant form. 255 255 Its total $z-$coordinate time derivative, 256 256 $\left. \frac{D u}{D t} \right|_z$ can be transformed as follows in order to obtain … … 272 272 + w \;\frac{\partial u}{\partial z} \\ 273 273 % 274 \intertext{introducing the chain rule (\autoref{ apdx:A_s_chain_rule}) }274 \intertext{introducing the chain rule (\autoref{eq:SCOORD_s_chain_rule}) } 275 275 % 276 276 &= \left. {\frac{\partial u }{\partial t}} \right|_z … … 306 306 \; \frac{\partial u}{\partial s} . \\ 307 307 % 308 \intertext{Introducing $\omega$, the dia-s-surface velocity given by (\autoref{ apdx:A_w_s}) }308 \intertext{Introducing $\omega$, the dia-s-surface velocity given by (\autoref{eq:SCOORD_w_s}) } 309 309 % 310 310 &= \left. {\frac{\partial u }{\partial t}} \right|_z … … 317 317 \end{subequations} 318 318 % 319 Applying the time derivative chain rule (first equation of (\autoref{ apdx:A_s_chain_rule})) to $u$ and320 using (\autoref{ apdx:A_w_in_s}) provides the expression of the last term of the right hand side,319 Applying the time derivative chain rule (first equation of (\autoref{eq:SCOORD_s_chain_rule})) to $u$ and 320 using (\autoref{eq:SCOORD_w_in_s}) provides the expression of the last term of the right hand side, 321 321 \[ 322 322 { … … 331 331 \ie\ the total $s-$coordinate time derivative : 332 332 \begin{align} 333 \label{ apdx:A_sco_Dt_vect}333 \label{eq:SCOORD_sco_Dt_vect} 334 334 \left. \frac{D u}{D t} \right|_s 335 335 = \left. {\frac{\partial u }{\partial t}} \right|_s 336 336 - \left. \zeta \right|_s \;v 337 337 + \frac{1}{2\,e_1}\left. {\frac{\partial (u^2+v^2)}{\partial i}} \right|_s 338 + \frac{1}{e_3 } \omega \;\frac{\partial u}{\partial s} . 338 + \frac{1}{e_3 } \omega \;\frac{\partial u}{\partial s} . 339 339 \end{align} 340 340 Therefore, the vector invariant form of the total time derivative has exactly the same mathematical form in … … 345 345 346 346 Let us start from the total time derivative in the curvilinear $s-$coordinate system we have just establish. 347 Following the procedure used to establish (\autoref{eq: PE_flux_form}), it can be transformed into :347 Following the procedure used to establish (\autoref{eq:MB_flux_form}), it can be transformed into : 348 348 % \begin{subequations} 349 349 \begin{align*} … … 367 367 \end{align*} 368 368 % 369 Introducing the vertical scale factor inside the horizontal derivative of the first two terms 369 Introducing the vertical scale factor inside the horizontal derivative of the first two terms 370 370 (\ie\ the horizontal divergence), it becomes : 371 371 \begin{align*} … … 373 373 \begin{array}{*{20}l} 374 374 % \begin{align*} {\begin{array}{*{20}l} 375 % {\begin{array}{*{20}l} \left. \frac{D u}{D t} \right|_s 375 % {\begin{array}{*{20}l} \left. \frac{D u}{D t} \right|_s 376 376 &= \left. {\frac{\partial u }{\partial t}} \right|_s 377 377 &+ \frac{1}{e_1\,e_2\,e_3} \left( \frac{\partial( e_2 e_3 \,u^2 )}{\partial i} … … 398 398 % 399 399 \intertext {Introducing a more compact form for the divergence of the momentum fluxes, 400 and using (\autoref{ apdx:A_sco_Continuity}), the $s-$coordinate continuity equation,400 and using (\autoref{eq:SCOORD_sco_Continuity}), the $s-$coordinate continuity equation, 401 401 it becomes : } 402 402 % … … 410 410 } 411 411 \end{align*} 412 which leads to the $s-$coordinate flux formulation of the total $s-$coordinate time derivative, 412 which leads to the $s-$coordinate flux formulation of the total $s-$coordinate time derivative, 413 413 \ie\ the total $s-$coordinate time derivative in flux form: 414 414 \begin{flalign} 415 \label{ apdx:A_sco_Dt_flux}415 \label{eq:SCOORD_sco_Dt_flux} 416 416 \left. \frac{D u}{D t} \right|_s = \frac{1}{e_3} \left. \frac{\partial ( e_3\,u)}{\partial t} \right|_s 417 417 + \left. \nabla \cdot \left( {{\mathrm {\mathbf U}}\,u} \right) \right|_s … … 422 422 It has the same form as in the $z-$coordinate but for 423 423 the vertical scale factor that has appeared inside the time derivative which 424 comes from the modification of (\autoref{ apdx:A_sco_Continuity}),424 comes from the modification of (\autoref{eq:SCOORD_sco_Continuity}), 425 425 the continuity equation. 426 426 … … 437 437 \] 438 438 Applying similar manipulation to the second component and 439 replacing $\sigma_1$ and $\sigma_2$ by their expression \autoref{ apdx:A_s_slope}, it becomes:440 \begin{equation} 441 \label{ apdx:A_grad_p_1}439 replacing $\sigma_1$ and $\sigma_2$ by their expression \autoref{eq:SCOORD_s_slope}, it becomes: 440 \begin{equation} 441 \label{eq:SCOORD_grad_p_1} 442 442 \begin{split} 443 443 -\frac{1}{\rho_o \, e_1 } \left. {\frac{\partial p}{\partial i}} \right|_z … … 451 451 \end{equation} 452 452 453 An additional term appears in (\autoref{ apdx:A_grad_p_1}) which accounts for453 An additional term appears in (\autoref{eq:SCOORD_grad_p_1}) which accounts for 454 454 the tilt of $s-$surfaces with respect to geopotential $z-$surfaces. 455 455 … … 467 467 Therefore, $p$ and $p_h'$ are linked through: 468 468 \begin{equation} 469 \label{ apdx:A_pressure}469 \label{eq:SCOORD_pressure} 470 470 p = \rho_o \; p_h' + \rho_o \, g \, ( \eta - z ) 471 471 \end{equation} … … 475 475 \] 476 476 477 Substituing \autoref{ apdx:A_pressure} in \autoref{apdx:A_grad_p_1} and477 Substituing \autoref{eq:SCOORD_pressure} in \autoref{eq:SCOORD_grad_p_1} and 478 478 using the definition of the density anomaly it becomes an expression in two parts: 479 479 \begin{equation} 480 \label{ apdx:A_grad_p_2}480 \label{eq:SCOORD_grad_p_2} 481 481 \begin{split} 482 482 -\frac{1}{\rho_o \, e_1 } \left. {\frac{\partial p}{\partial i}} \right|_z … … 491 491 This formulation of the pressure gradient is characterised by the appearance of 492 492 a term depending on the sea surface height only 493 (last term on the right hand side of expression \autoref{ apdx:A_grad_p_2}).493 (last term on the right hand side of expression \autoref{eq:SCOORD_grad_p_2}). 494 494 This term will be loosely termed \textit{surface pressure gradient} whereas 495 495 the first term will be termed the \textit{hydrostatic pressure gradient} by analogy to … … 502 502 The coriolis and forcing terms as well as the the vertical physics remain unchanged as 503 503 they involve neither time nor space derivatives. 504 The form of the lateral physics is discussed in \autoref{apdx: B}.504 The form of the lateral physics is discussed in \autoref{apdx:DIFFOPERS}. 505 505 506 506 $\bullet$ \textbf{Full momentum equation} … … 510 510 the one in a curvilinear $z-$coordinate, except for the pressure gradient term: 511 511 \begin{subequations} 512 \label{ apdx:A_dyn_vect}512 \label{eq:SCOORD_dyn_vect} 513 513 \begin{multline} 514 \label{ apdx:A_PE_dyn_vect_u}514 \label{eq:SCOORD_PE_dyn_vect_u} 515 515 \frac{\partial u}{\partial t}= 516 516 + \left( {\zeta +f} \right)\,v … … 522 522 \end{multline} 523 523 \begin{multline} 524 \label{ apdx:A_dyn_vect_v}524 \label{eq:SCOORD_dyn_vect_v} 525 525 \frac{\partial v}{\partial t}= 526 526 - \left( {\zeta +f} \right)\,u … … 535 535 the formulation of both the time derivative and the pressure gradient term: 536 536 \begin{subequations} 537 \label{ apdx:A_dyn_flux}537 \label{eq:SCOORD_dyn_flux} 538 538 \begin{multline} 539 \label{ apdx:A_PE_dyn_flux_u}539 \label{eq:SCOORD_PE_dyn_flux_u} 540 540 \frac{1}{e_3} \frac{\partial \left( e_3\,u \right) }{\partial t} = 541 541 - \nabla \cdot \left( {{\mathrm {\mathbf U}}\,u} \right) … … 547 547 \end{multline} 548 548 \begin{multline} 549 \label{ apdx:A_dyn_flux_v}549 \label{eq:SCOORD_dyn_flux_v} 550 550 \frac{1}{e_3}\frac{\partial \left( e_3\,v \right) }{\partial t}= 551 551 - \nabla \cdot \left( {{\mathrm {\mathbf U}}\,v} \right) … … 554 554 - \frac{1}{e_2 } \left( \frac{\partial p_h'}{\partial j} + g\; d \; \frac{\partial z}{\partial j} \right) 555 555 - \frac{g}{e_2 } \frac{\partial \eta}{\partial j} 556 + D_v^{\vect{U}} + F_v^{\vect{U}} . 556 + D_v^{\vect{U}} + F_v^{\vect{U}} . 557 557 \end{multline} 558 558 \end{subequations} … … 560 560 hydrostatic pressure and density anomalies, $p_h'$ and $d=( \frac{\rho}{\rho_o}-1 )$: 561 561 \begin{equation} 562 \label{ apdx:A_dyn_zph}562 \label{eq:SCOORD_dyn_zph} 563 563 \frac{\partial p_h'}{\partial k} = - d \, g \, e_3 . 564 564 \end{equation} … … 569 569 in particular the pressure gradient. 570 570 By contrast, $\omega$ is not $w$, the third component of the velocity, but the dia-surface velocity component, 571 \ie\ the volume flux across the moving $s$-surfaces per unit horizontal area. 571 \ie\ the volume flux across the moving $s$-surfaces per unit horizontal area. 572 572 573 573 … … 576 576 % ================================================================ 577 577 \section{Tracer equation} 578 \label{sec: A_tracer}578 \label{sec:SCOORD_tracer} 579 579 580 580 The tracer equation is obtained using the same calculation as for the continuity equation and then … … 582 582 583 583 \begin{multline} 584 \label{ apdx:A_tracer}584 \label{eq:SCOORD_tracer} 585 585 \frac{1}{e_3} \frac{\partial \left( e_3 T \right)}{\partial t} 586 586 = -\frac{1}{e_1 \,e_2 \,e_3} … … 591 591 \end{multline} 592 592 593 The expression for the advection term is a straight consequence of (\autoref{ apdx:A_sco_Continuity}),594 the expression of the 3D divergence in the $s-$coordinates established above. 593 The expression for the advection term is a straight consequence of (\autoref{eq:SCOORD_sco_Continuity}), 594 the expression of the 3D divergence in the $s-$coordinates established above. 595 595 596 596 \biblio -
NEMO/trunk/doc/latex/NEMO/subfiles/apdx_triads.tex
r11529 r11543 16 16 % ================================================================ 17 17 \chapter{Iso-Neutral Diffusion and Eddy Advection using Triads} 18 \label{apdx: triad}18 \label{apdx:TRIADS} 19 19 20 20 \chaptertoc … … 45 45 \begin{description} 46 46 \item[\np{ln\_triad\_iso}] 47 See \autoref{sec: taper}.47 See \autoref{sec:TRIADS_taper}. 48 48 If this is set false (the default), 49 49 then `iso-neutral' mixing is accomplished within the surface mixed-layer along slopes linearly decreasing with 50 depth from the value immediately below the mixed-layer to zero (flat) at the surface (\autoref{sec: lintaper}).50 depth from the value immediately below the mixed-layer to zero (flat) at the surface (\autoref{sec:TRIADS_lintaper}). 51 51 This is the same treatment as used in the default implementation 52 \autoref{subsec:LDF_slp_iso}; \autoref{fig: eiv_slp}.52 \autoref{subsec:LDF_slp_iso}; \autoref{fig:LDF_eiv_slp}. 53 53 Where \np{ln\_triad\_iso} is set true, 54 54 the vertical skew flux is further reduced to ensure no vertical buoyancy flux, 55 55 giving an almost pure horizontal diffusive tracer flux within the mixed layer. 56 This is similar to the tapering suggested by \citet{gerdes.koberle.ea_CD91}. See \autoref{subsec: Gerdes-taper}56 This is similar to the tapering suggested by \citet{gerdes.koberle.ea_CD91}. See \autoref{subsec:TRIADS_Gerdes-taper} 57 57 \item[\np{ln\_botmix\_triad}] 58 See \autoref{sec: iso_bdry}.58 See \autoref{sec:TRIADS_iso_bdry}. 59 59 If this is set false (the default) then the lateral diffusive fluxes 60 associated with triads partly masked by topography are neglected. 61 If it is set true, however, then these lateral diffusive fluxes are applied, 60 associated with triads partly masked by topography are neglected. 61 If it is set true, however, then these lateral diffusive fluxes are applied, 62 62 giving smoother bottom tracer fields at the cost of introducing diapycnal mixing. 63 63 \item[\np{rn\_sw\_triad}] … … 71 71 72 72 \section{Triad formulation of iso-neutral diffusion} 73 \label{sec: iso}73 \label{sec:TRIADS_iso} 74 74 75 75 We have implemented into \NEMO\ a scheme inspired by \citet{griffies.gnanadesikan.ea_JPO98}, … … 79 79 80 80 The iso-neutral second order tracer diffusive operator for small angles between 81 iso-neutral surfaces and geopotentials is given by \autoref{eq: iso_tensor_1}:81 iso-neutral surfaces and geopotentials is given by \autoref{eq:TRIADS_iso_tensor_1}: 82 82 \begin{subequations} 83 \label{eq: iso_tensor_1}83 \label{eq:TRIADS_iso_tensor_1} 84 84 \begin{equation} 85 85 D^{lT}=-\nabla \cdot\vect{f}^{lT}\equiv … … 92 92 \end{equation} 93 93 \begin{equation} 94 \label{eq: iso_tensor_2}94 \label{eq:TRIADS_iso_tensor_2} 95 95 \mbox{with}\quad \;\;\Re = 96 96 \begin{pmatrix} … … 113 113 % {-r_1 } \hfill & {-r_2 } \hfill & {r_1 ^2+r_2 ^2} \hfill \\ 114 114 % \end{array} }} \right) 115 Here \autoref{eq: PE_iso_slopes}115 Here \autoref{eq:MB_iso_slopes} 116 116 \begin{align*} 117 117 r_1 &=-\frac{e_3 }{e_1 } \left( \frac{\partial \rho }{\partial i} … … 128 128 We will find it useful to consider the fluxes per unit area in $i,j,k$ space; we write 129 129 \[ 130 % \label{eq: Fijk}130 % \label{eq:TRIADS_Fijk} 131 131 \vect{F}_{\mathrm{iso}}=\left(f_1^{lT}e_2e_3, f_2^{lT}e_1e_3, f_3^{lT}e_1e_2\right). 132 132 \] … … 136 136 137 137 The off-diagonal terms of the small angle diffusion tensor 138 \autoref{eq: iso_tensor_1}, \autoref{eq:iso_tensor_2} produce skew-fluxes along138 \autoref{eq:TRIADS_iso_tensor_1}, \autoref{eq:TRIADS_iso_tensor_2} produce skew-fluxes along 139 139 the $i$- and $j$-directions resulting from the vertical tracer gradient: 140 140 \begin{align} 141 \label{eq: i13c}141 \label{eq:TRIADS_i13c} 142 142 f_{13}=&+{A^{lT}} r_1\frac{1}{e_3}\frac{\partial T}{\partial k},\qquad f_{23}=+{A^{lT}} r_2\frac{1}{e_3}\frac{\partial T}{\partial k}\\ 143 143 \intertext{and in the k-direction resulting from the lateral tracer gradients} 144 \label{eq: i31c}144 \label{eq:TRIADS_i31c} 145 145 f_{31}+f_{32}=& {A^{lT}} r_1\frac{1}{e_1}\frac{\partial T}{\partial i}+{A^{lT}} r_2\frac{1}{e_1}\frac{\partial T}{\partial i} 146 146 \end{align} … … 148 148 The vertical diffusive flux associated with the $_{33}$ component of the small angle diffusion tensor is 149 149 \begin{equation} 150 \label{eq: i33c}150 \label{eq:TRIADS_i33c} 151 151 f_{33}=-{A^{lT}}(r_1^2 +r_2^2) \frac{1}{e_3}\frac{\partial T}{\partial k}. 152 152 \end{equation} … … 157 157 The following description will describe the fluxes on the $i$-$k$ plane. 158 158 159 There is no natural discretization for the $i$-component of the skew-flux, \autoref{eq: i13c},159 There is no natural discretization for the $i$-component of the skew-flux, \autoref{eq:TRIADS_i13c}, 160 160 as although it must be evaluated at $u$-points, 161 161 it involves vertical gradients (both for the tracer and the slope $r_1$), defined at $w$-points. 162 Similarly, the vertical skew flux, \autoref{eq: i31c},162 Similarly, the vertical skew flux, \autoref{eq:TRIADS_i31c}, 163 163 is evaluated at $w$-points but involves horizontal gradients defined at $u$-points. 164 164 … … 166 166 167 167 The straightforward approach to discretize the lateral skew flux 168 \autoref{eq: i13c} from tracer cell $i,k$ to $i+1,k$, introduced in 1995 into OPA,169 \autoref{eq: tra_ldf_iso}, is to calculate a mean vertical gradient at the $u$-point from168 \autoref{eq:TRIADS_i13c} from tracer cell $i,k$ to $i+1,k$, introduced in 1995 into OPA, 169 \autoref{eq:TRA_ldf_iso}, is to calculate a mean vertical gradient at the $u$-point from 170 170 the average of the four surrounding vertical tracer gradients, and multiply this by a mean slope at the $u$-point, 171 171 calculated from the averaged surrounding vertical density gradients. 172 172 The total area-integrated skew-flux (flux per unit area in $ijk$ space) from tracer cell $i,k$ to $i+1,k$, 173 173 noting that the $e_{{3}_{i+1/2}^k}$ in the area $e{_{3}}_{i+1/2}^k{e_{2}}_{i+1/2}i^k$ at the $u$-point cancels out with 174 the $1/{e_{3}}_{i+1/2}^k$ associated with the vertical tracer gradient, is then \autoref{eq: tra_ldf_iso}174 the $1/{e_{3}}_{i+1/2}^k$ associated with the vertical tracer gradient, is then \autoref{eq:TRA_ldf_iso} 175 175 \[ 176 176 \left(F_u^{13} \right)_{i+\frac{1}{2}}^k = {A}_{i+\frac{1}{2}}^k … … 205 205 \includegraphics[width=\textwidth]{Fig_GRIFF_triad_fluxes} 206 206 \caption{ 207 \protect\label{fig: ISO_triad}207 \protect\label{fig:TRIADS_ISO_triad} 208 208 (a) Arrangement of triads $S_i$ and tracer gradients to 209 209 give lateral tracer flux from box $i,k$ to $i+1,k$ … … 217 217 the corresponding `triad' slope calculated from the lateral density gradient across the $u$-point divided by 218 218 the vertical density gradient at the same $w$-point as the tracer gradient. 219 See \autoref{fig: ISO_triad}a, where the thick lines denote the tracer gradients,219 See \autoref{fig:TRIADS_ISO_triad}a, where the thick lines denote the tracer gradients, 220 220 and the thin lines the corresponding triads, with slopes $s_1, \dotsc s_4$. 221 221 The total area-integrated skew-flux from tracer cell $i,k$ to $i+1,k$ 222 222 \begin{multline} 223 \label{eq: i13}223 \label{eq:TRIADS_i13} 224 224 \left( F_u^{13} \right)_{i+\frac{1}{2}}^k = {A}_{i+1}^k a_1 s_1 225 225 \delta_{k+\frac{1}{2}} \left[ T^{i+1} … … 235 235 This discretization gives a much closer stencil, and disallows the two-point computational modes. 236 236 237 The vertical skew flux \autoref{eq: i31c} from tracer cell $i,k$ to $i,k+1$ at238 the $w$-point $i,k+\frac{1}{2}$ is constructed similarly (\autoref{fig: ISO_triad}b) by237 The vertical skew flux \autoref{eq:TRIADS_i31c} from tracer cell $i,k$ to $i,k+1$ at 238 the $w$-point $i,k+\frac{1}{2}$ is constructed similarly (\autoref{fig:TRIADS_ISO_triad}b) by 239 239 multiplying lateral tracer gradients from each of the four surrounding $u$-points by the appropriate triad slope: 240 240 \begin{multline} 241 \label{eq: i31}241 \label{eq:TRIADS_i31} 242 242 \left( F_w^{31} \right) _i ^{k+\frac{1}{2}} = {A}_i^{k+1} a_{1}' 243 243 s_{1}' \delta_{i-\frac{1}{2}} \left[ T^{k+1} \right]/{e_{3u}}_{i-\frac{1}{2}}^{k+1} … … 250 250 (appearing in both the vertical and lateral gradient), 251 251 and the $u$- and $w$-points $(i+i_p,k)$, $(i,k+k_p)$ at the centres of the `arms' of the triad as follows 252 (see also \autoref{fig: ISO_triad}):253 \begin{equation} 254 \label{eq: R}252 (see also \autoref{fig:TRIADS_ISO_triad}): 253 \begin{equation} 254 \label{eq:TRIADS_R} 255 255 _i^k \mathbb{R}_{i_p}^{k_p} 256 256 =-\frac{ {e_{3w}}_{\,i}^{\,k+k_p}} { {e_{1u}}_{\,i+i_p}^{\,k}} … … 269 269 \includegraphics[width=\textwidth]{Fig_GRIFF_qcells} 270 270 \caption{ 271 \protect\label{fig: qcells}271 \protect\label{fig:TRIADS_qcells} 272 272 Triad notation for quarter cells. $T$-cells are inside boxes, 273 273 while the $i+\fractext{1}{2},k$ $u$-cell is shaded in green and … … 278 278 % >>>>>>>>>>>>>>>>>>>>>>>>>>>> 279 279 280 Each triad $\{_i^{k}\:_{i_p}^{k_p}\}$ is associated (\autoref{fig: qcells}) with the quarter cell that is280 Each triad $\{_i^{k}\:_{i_p}^{k_p}\}$ is associated (\autoref{fig:TRIADS_qcells}) with the quarter cell that is 281 281 the intersection of the $i,k$ $T$-cell, the $i+i_p,k$ $u$-cell and the $i,k+k_p$ $w$-cell. 282 Expressing the slopes $s_i$ and $s'_i$ in \autoref{eq: i13} and \autoref{eq:i31} in this notation,282 Expressing the slopes $s_i$ and $s'_i$ in \autoref{eq:TRIADS_i13} and \autoref{eq:TRIADS_i31} in this notation, 283 283 we have \eg\ \ $s_1=s'_1={\:}_i^k \mathbb{R}_{1/2}^{1/2}$. 284 284 Each triad slope $_i^k\mathbb{R}_{i_p}^{k_p}$ is used once (as an $s$) to … … 289 289 and we notate these areas, similarly to the triad slopes, 290 290 as $_i^k{\mathbb{A}_u}_{i_p}^{k_p}$, $_i^k{\mathbb{A}_w}_{i_p}^{k_p}$, 291 where \eg\ in \autoref{eq: i13} $a_{1}={\:}_i^k{\mathbb{A}_u}_{1/2}^{1/2}$,292 and in \autoref{eq: i31} $a'_{1}={\:}_i^k{\mathbb{A}_w}_{1/2}^{1/2}$.291 where \eg\ in \autoref{eq:TRIADS_i13} $a_{1}={\:}_i^k{\mathbb{A}_u}_{1/2}^{1/2}$, 292 and in \autoref{eq:TRIADS_i31} $a'_{1}={\:}_i^k{\mathbb{A}_w}_{1/2}^{1/2}$. 293 293 294 294 \subsection{Full triad fluxes} … … 299 299 tracer cell $i,k$ to $i+1,k$ coming from the $_{11}$ term of the diffusion tensor takes the form 300 300 \begin{equation} 301 \label{eq: i11}301 \label{eq:TRIADS_i11} 302 302 \left( F_u^{11} \right) _{i+\frac{1}{2}} ^{k} = 303 303 - \left( {A}_i^{k+1} a_{1} + {A}_i^{k+1} a_{2} + {A}_i^k … … 305 305 \frac{\delta_{i+1/2} \left[ T^k\right]}{{e_{1u}}_{\,i+1/2}^{\,k}}, 306 306 \end{equation} 307 where the areas $a_i$ are as in \autoref{eq: i13}.308 In this case, separating the total lateral flux, the sum of \autoref{eq: i13} and \autoref{eq:i11},307 where the areas $a_i$ are as in \autoref{eq:TRIADS_i13}. 308 In this case, separating the total lateral flux, the sum of \autoref{eq:TRIADS_i13} and \autoref{eq:TRIADS_i11}, 309 309 into triad components, a lateral tracer flux 310 310 \begin{equation} 311 \label{eq: latflux-triad}311 \label{eq:TRIADS_latflux-triad} 312 312 _i^k {\mathbb{F}_u}_{i_p}^{k_p} (T) = - {A}_i^k{ \:}_i^k{\mathbb{A}_u}_{i_p}^{k_p} 313 313 \left( … … 322 322 the lateral density flux associated with each triad separately disappears. 323 323 \begin{equation} 324 \label{eq: latflux-rho}324 \label{eq:TRIADS_latflux-rho} 325 325 {\mathbb{F}_u}_{i_p}^{k_p} (\rho)=-\alpha _i^k {\:}_i^k {\mathbb{F}_u}_{i_p}^{k_p} (T) + \beta_i^k {\:}_i^k {\mathbb{F}_u}_{i_p}^{k_p} (S)=0 326 326 \end{equation} … … 328 328 tracer cell $i,k$ to $i+1,k$ must also vanish since it is a sum of four such triad fluxes. 329 329 330 The squared slope $r_1^2$ in the expression \autoref{eq: i33c} for the $_{33}$ component is also expressed in330 The squared slope $r_1^2$ in the expression \autoref{eq:TRIADS_i33c} for the $_{33}$ component is also expressed in 331 331 terms of area-weighted squared triad slopes, 332 332 so the area-integrated vertical flux from tracer cell $i,k$ to $i,k+1$ resulting from the $r_1^2$ term is 333 333 \begin{equation} 334 \label{eq: i33}334 \label{eq:TRIADS_i33} 335 335 \left( F_w^{33} \right) _i^{k+\frac{1}{2}} = 336 336 - \left( {A}_i^{k+1} a_{1}' s_{1}'^2 … … 339 339 + {A}_i^k a_{4}' s_{4}'^2 \right)\delta_{k+\frac{1}{2}} \left[ T^{i+1} \right], 340 340 \end{equation} 341 where the areas $a'$ and slopes $s'$ are the same as in \autoref{eq: i31}.342 Then, separating the total vertical flux, the sum of \autoref{eq: i31} and \autoref{eq:i33},341 where the areas $a'$ and slopes $s'$ are the same as in \autoref{eq:TRIADS_i31}. 342 Then, separating the total vertical flux, the sum of \autoref{eq:TRIADS_i31} and \autoref{eq:TRIADS_i33}, 343 343 into triad components, a vertical flux 344 344 \begin{align} 345 \label{eq: vertflux-triad}345 \label{eq:TRIADS_vertflux-triad} 346 346 _i^k {\mathbb{F}_w}_{i_p}^{k_p} (T) 347 347 &= {A}_i^k{\: }_i^k{\mathbb{A}_w}_{i_p}^{k_p} … … 352 352 \right) \\ 353 353 &= - \left(\left.{ }_i^k{\mathbb{A}_w}_{i_p}^{k_p}\right/{ }_i^k{\mathbb{A}_u}_{i_p}^{k_p}\right) 354 {_i^k\mathbb{R}_{i_p}^{k_p}}{\: }_i^k{\mathbb{F}_u}_{i_p}^{k_p} (T) \label{eq: vertflux-triad2}354 {_i^k\mathbb{R}_{i_p}^{k_p}}{\: }_i^k{\mathbb{F}_u}_{i_p}^{k_p} (T) \label{eq:TRIADS_vertflux-triad2} 355 355 \end{align} 356 356 may be associated with each triad. … … 361 361 tracer cell $i,k$ to $i,k+1$ must also vanish since it is a sum of four such triad fluxes. 362 362 363 We can explicitly identify (\autoref{fig: qcells}) the triads associated with the $s_i$, $a_i$,364 and $s'_i$, $a'_i$ used in the definition of the $u$-fluxes and $w$-fluxes in \autoref{eq: i31},365 \autoref{eq: i13}, \autoref{eq:i11} \autoref{eq:i33} and \autoref{fig:ISO_triad} to write out363 We can explicitly identify (\autoref{fig:TRIADS_qcells}) the triads associated with the $s_i$, $a_i$, 364 and $s'_i$, $a'_i$ used in the definition of the $u$-fluxes and $w$-fluxes in \autoref{eq:TRIADS_i31}, 365 \autoref{eq:TRIADS_i13}, \autoref{eq:TRIADS_i11} \autoref{eq:TRIADS_i33} and \autoref{fig:TRIADS_ISO_triad} to write out 366 366 the iso-neutral fluxes at $u$- and $w$-points as sums of the triad fluxes that cross the $u$- and $w$-faces: 367 %(\autoref{fig: ISO_triad}):367 %(\autoref{fig:TRIADS_ISO_triad}): 368 368 \begin{flalign} 369 \label{eq: iso_flux} \vect{F}_{\mathrm{iso}}(T) &\equiv369 \label{eq:TRIADS_iso_flux} \vect{F}_{\mathrm{iso}}(T) &\equiv 370 370 \sum_{\substack{i_p,\,k_p}} 371 371 \begin{pmatrix} … … 376 376 377 377 \subsection{Ensuring the scheme does not increase tracer variance} 378 \label{subsec: variance}378 \label{subsec:TRIADS_variance} 379 379 380 380 We now require that this operator should not increase the globally-integrated tracer variance. … … 400 400 &= -T_{i+i_p-1/2}^k{\;} _i^k{\mathbb{F}_u}_{i_p}^{k_p} (T) \quad + \quad T_{i+i_p+1/2}^k 401 401 {\;}_i^k{\mathbb{F}_u}_{i_p}^{k_p} (T) \\ 402 &={\;} _i^k{\mathbb{F}_u}_{i_p}^{k_p} (T)\,\delta_{i+ i_p}[T^k], \label{eq: dvar_iso_i}402 &={\;} _i^k{\mathbb{F}_u}_{i_p}^{k_p} (T)\,\delta_{i+ i_p}[T^k], \label{eq:TRIADS_dvar_iso_i} 403 403 \end{aligned} 404 404 \end{multline} … … 406 406 the $T$-points $i,k+k_p-\fractext{1}{2}$ (above) and $i,k+k_p+\fractext{1}{2}$ (below) of 407 407 \begin{equation} 408 \label{eq: dvar_iso_k}408 \label{eq:TRIADS_dvar_iso_k} 409 409 _i^k{\mathbb{F}_w}_{i_p}^{k_p} (T) \,\delta_{k+ k_p}[T^i]. 410 410 \end{equation} 411 411 The total variance tendency driven by the triad is the sum of these two. 412 412 Expanding $_i^k{\mathbb{F}_u}_{i_p}^{k_p} (T)$ and $_i^k{\mathbb{F}_w}_{i_p}^{k_p} (T)$ with 413 \autoref{eq: latflux-triad} and \autoref{eq:vertflux-triad}, it is413 \autoref{eq:TRIADS_latflux-triad} and \autoref{eq:TRIADS_vertflux-triad}, it is 414 414 \begin{multline*} 415 415 -{A}_i^k\left \{ … … 430 430 be related to a triad volume $_i^k\mathbb{V}_{i_p}^{k_p}$ by 431 431 \begin{equation} 432 \label{eq: V-A}432 \label{eq:TRIADS_V-A} 433 433 _i^k\mathbb{V}_{i_p}^{k_p} 434 434 ={\;}_i^k{\mathbb{A}_u}_{i_p}^{k_p}\,{e_{1u}}_{\,i + i_p}^{\,k} … … 437 437 the variance tendency reduces to the perfect square 438 438 \begin{equation} 439 \label{eq: perfect-square}439 \label{eq:TRIADS_perfect-square} 440 440 -{A}_i^k{\:} _i^k\mathbb{V}_{i_p}^{k_p} 441 441 \left( … … 445 445 \right)^2\leq 0. 446 446 \end{equation} 447 Thus, the constraint \autoref{eq: V-A} ensures that the fluxes448 (\autoref{eq: latflux-triad}, \autoref{eq:vertflux-triad}) associated with447 Thus, the constraint \autoref{eq:TRIADS_V-A} ensures that the fluxes 448 (\autoref{eq:TRIADS_latflux-triad}, \autoref{eq:TRIADS_vertflux-triad}) associated with 449 449 a given slope triad $_i^k\mathbb{R}_{i_p}^{k_p}$ do not increase the net variance. 450 450 Since the total fluxes are sums of such fluxes from the various triads, this constraint, applied to all triads, 451 451 is sufficient to ensure that the globally integrated variance does not increase. 452 452 453 The expression \autoref{eq: V-A} can be interpreted as a discretization of the global integral454 \begin{equation} 455 \label{eq: cts-var}453 The expression \autoref{eq:TRIADS_V-A} can be interpreted as a discretization of the global integral 454 \begin{equation} 455 \label{eq:TRIADS_cts-var} 456 456 \frac{\partial}{\partial t}\int\!\fractext{1}{2} T^2\, dV = 457 457 \int\!\mathbf{F}\cdot\nabla T\, dV, … … 477 477 \citet{griffies.gnanadesikan.ea_JPO98} identifies these $_i^k\mathbb{V}_{i_p}^{k_p}$ as the volumes of the quarter cells, 478 478 defined in terms of the distances between $T$, $u$,$f$ and $w$-points. 479 This is the natural discretization of \autoref{eq: cts-var}.479 This is the natural discretization of \autoref{eq:TRIADS_cts-var}. 480 480 The \NEMO\ model, however, operates with scale factors instead of grid sizes, 481 481 and scale factors for the quarter cells are not defined. 482 482 Instead, therefore we simply choose 483 483 \begin{equation} 484 \label{eq: V-NEMO}484 \label{eq:TRIADS_V-NEMO} 485 485 _i^k\mathbb{V}_{i_p}^{k_p}=\fractext{1}{4} {b_u}_{i+i_p}^k, 486 486 \end{equation} … … 489 489 the lateral flux from tracer cell $i,k$ to $i+1,k$ reduces to the classical form 490 490 \begin{equation} 491 \label{eq: lat-normal}491 \label{eq:TRIADS_lat-normal} 492 492 -\overline{A}_{\,i+1/2}^k\; 493 493 \frac{{b_u}_{i+1/2}^k}{{e_{1u}}_{\,i + i_p}^{\,k}} … … 497 497 In fact if the diffusive coefficient is defined at $u$-points, 498 498 so that we employ ${A}_{i+i_p}^k$ instead of ${A}_i^k$ in the definitions of the triad fluxes 499 \autoref{eq: latflux-triad} and \autoref{eq:vertflux-triad},499 \autoref{eq:TRIADS_latflux-triad} and \autoref{eq:TRIADS_vertflux-triad}, 500 500 we can replace $\overline{A}_{\,i+1/2}^k$ by $A_{i+1/2}^k$ in the above. 501 501 … … 503 503 504 504 The iso-neutral fluxes at $u$- and $w$-points are the sums of the triad fluxes that 505 cross the $u$- and $w$-faces \autoref{eq: iso_flux}:505 cross the $u$- and $w$-faces \autoref{eq:TRIADS_iso_flux}: 506 506 \begin{subequations} 507 % \label{eq: alltriadflux}507 % \label{eq:TRIADS_alltriadflux} 508 508 \begin{flalign*} 509 % \label{eq: vect_isoflux}509 % \label{eq:TRIADS_vect_isoflux} 510 510 \vect{F}_{\mathrm{iso}}(T) &\equiv 511 511 \sum_{\substack{i_p,\,k_p}} … … 515 515 \end{pmatrix}, 516 516 \end{flalign*} 517 where \autoref{eq: latflux-triad}:517 where \autoref{eq:TRIADS_latflux-triad}: 518 518 \begin{align} 519 \label{eq: triadfluxu}519 \label{eq:TRIADS_triadfluxu} 520 520 _i^k {\mathbb{F}_u}_{i_p}^{k_p} (T) &= - {A}_i^k{ 521 521 \:}\frac{{{}_i^k\mathbb{V}}_{i_p}^{k_p}}{{e_{1u}}_{\,i + i_p}^{\,k}} … … 532 532 -\ \left({_i^k\mathbb{R}_{i_p}^{k_p}}\right)^2 \ 533 533 \frac{ \delta_{k+k_p} [T^i] }{{e_{3w}}_{\,i}^{\,k+k_p} } 534 \right),\label{eq: triadfluxw}534 \right),\label{eq:TRIADS_triadfluxw} 535 535 \end{align} 536 with \autoref{eq: V-NEMO}536 with \autoref{eq:TRIADS_V-NEMO} 537 537 \[ 538 % \label{eq: V-NEMO2}538 % \label{eq:TRIADS_V-NEMO2} 539 539 _i^k{\mathbb{V}}_{i_p}^{k_p}=\fractext{1}{4} {b_u}_{i+i_p}^k. 540 540 \] 541 541 \end{subequations} 542 542 543 The divergence of the expression \autoref{eq: iso_flux} for the fluxes gives the iso-neutral diffusion tendency at543 The divergence of the expression \autoref{eq:TRIADS_iso_flux} for the fluxes gives the iso-neutral diffusion tendency at 544 544 each tracer point: 545 545 \[ 546 % \label{eq: iso_operator}546 % \label{eq:TRIADS_iso_operator} 547 547 D_l^T = \frac{1}{b_T} 548 548 \sum_{\substack{i_p,\,k_p}} \left\{ \delta_{i} \left[{_{i+1/2-i_p}^k … … 555 555 \item[$\bullet$ horizontal diffusion] 556 556 The discretization of the diffusion operator recovers the traditional five-point Laplacian 557 \autoref{eq: lat-normal} in the limit of flat iso-neutral direction:557 \autoref{eq:TRIADS_lat-normal} in the limit of flat iso-neutral direction: 558 558 \[ 559 % \label{eq: iso_property0}559 % \label{eq:TRIADS_iso_property0} 560 560 D_l^T = \frac{1}{b_T} \ 561 561 \delta_{i} \left[ \frac{e_{2u}\,e_{3u}}{e_{1u}} \; … … 565 565 566 566 \item[$\bullet$ implicit treatment in the vertical] 567 Only tracer values associated with a single water column appear in the expression \autoref{eq: i33} for567 Only tracer values associated with a single water column appear in the expression \autoref{eq:TRIADS_i33} for 568 568 the $_{33}$ fluxes, vertical fluxes driven by vertical gradients. 569 569 This is of paramount importance since it means that a time-implicit algorithm can be used to … … 582 582 \item[$\bullet$ pure iso-neutral operator] 583 583 The iso-neutral flux of locally referenced potential density is zero. 584 See \autoref{eq: latflux-rho} and \autoref{eq:vertflux-triad2}.584 See \autoref{eq:TRIADS_latflux-rho} and \autoref{eq:TRIADS_vertflux-triad2}. 585 585 586 586 \item[$\bullet$ conservation of tracer] 587 587 The iso-neutral diffusion conserves tracer content, \ie 588 588 \[ 589 % \label{eq: iso_property1}589 % \label{eq:TRIADS_iso_property1} 590 590 \sum_{i,j,k} \left\{ D_l^T \ b_T \right\} = 0 591 591 \] … … 595 595 The iso-neutral diffusion does not increase the tracer variance, \ie 596 596 \[ 597 % \label{eq: iso_property2}597 % \label{eq:TRIADS_iso_property2} 598 598 \sum_{i,j,k} \left\{ T \ D_l^T \ b_T \right\} \leq 0 599 599 \] 600 The property is demonstrated in \autoref{subsec: variance} above.600 The property is demonstrated in \autoref{subsec:TRIADS_variance} above. 601 601 It is a key property for a diffusion term. 602 602 It means that it is also a dissipation term, … … 608 608 The iso-neutral diffusion operator is self-adjoint, \ie 609 609 \begin{equation} 610 \label{eq: iso_property3}610 \label{eq:TRIADS_iso_property3} 611 611 \sum_{i,j,k} \left\{ S \ D_l^T \ b_T \right\} = \sum_{i,j,k} \left\{ D_l^S \ T \ b_T \right\} 612 612 \end{equation} … … 614 614 We just have to apply the same routine. 615 615 This property can be demonstrated similarly to the proof of the `no increase of tracer variance' property. 616 The contribution by a single triad towards the left hand side of \autoref{eq: iso_property3},617 can be found by replacing $\delta[T]$ by $\delta[S]$ in \autoref{eq: dvar_iso_i} and \autoref{eq:dvar_iso_k}.618 This results in a term similar to \autoref{eq: perfect-square},616 The contribution by a single triad towards the left hand side of \autoref{eq:TRIADS_iso_property3}, 617 can be found by replacing $\delta[T]$ by $\delta[S]$ in \autoref{eq:TRIADS_dvar_iso_i} and \autoref{eq:TRIADS_dvar_iso_k}. 618 This results in a term similar to \autoref{eq:TRIADS_perfect-square}, 619 619 \[ 620 % \label{eq:T Scovar}620 % \label{eq:TRIADS_TScovar} 621 621 - {A}_i^k{\:} _i^k\mathbb{V}_{i_p}^{k_p} 622 622 \left( … … 632 632 \] 633 633 This is symmetrical in $T $ and $S$, so exactly the same term arises from 634 the discretization of this triad's contribution towards the RHS of \autoref{eq: iso_property3}.634 the discretization of this triad's contribution towards the RHS of \autoref{eq:TRIADS_iso_property3}. 635 635 \end{description} 636 636 637 637 \subsection{Treatment of the triads at the boundaries} 638 \label{sec: iso_bdry}638 \label{sec:TRIADS_iso_bdry} 639 639 640 640 The triad slope can only be defined where both the grid boxes centred at the end of the arms exist. 641 641 Triads that would poke up through the upper ocean surface into the atmosphere, 642 642 or down into the ocean floor, must be masked out. 643 See \autoref{fig: bdry_triads}.643 See \autoref{fig:TRIADS_bdry_triads}. 644 644 Surface layer triads \triad{i}{1}{R}{1/2}{-1/2} (magenta) and \triad{i+1}{1}{R}{-1/2}{-1/2} (blue) that 645 require density to be specified above the ocean surface are masked (\autoref{fig: bdry_triads}a):645 require density to be specified above the ocean surface are masked (\autoref{fig:TRIADS_bdry_triads}a): 646 646 this ensures that lateral tracer gradients produce no flux through the ocean surface. 647 647 However, to prevent surface noise, it is customary to retain the $_{11}$ contributions towards 648 648 the lateral triad fluxes \triad[u]{i}{1}{F}{1/2}{-1/2} and \triad[u]{i+1}{1}{F}{-1/2}{-1/2}; 649 649 this drives diapycnal tracer fluxes. 650 Similar comments apply to triads that would intersect the ocean floor (\autoref{fig: bdry_triads}b).650 Similar comments apply to triads that would intersect the ocean floor (\autoref{fig:TRIADS_bdry_triads}b). 651 651 Note that both near bottom triad slopes \triad{i}{k}{R}{1/2}{1/2} and \triad{i+1}{k}{R}{-1/2}{1/2} are masked when 652 652 either of the $i,k+1$ or $i+1,k+1$ tracer points is masked, \ie\ the $i,k+1$ $u$-point is masked. … … 662 662 \includegraphics[width=\textwidth]{Fig_GRIFF_bdry_triads} 663 663 \caption{ 664 \protect\label{fig: bdry_triads}664 \protect\label{fig:TRIADS_bdry_triads} 665 665 (a) Uppermost model layer $k=1$ with $i,1$ and $i+1,1$ tracer points (black dots), 666 666 and $i+1/2,1$ $u$-point (blue square). … … 683 683 684 684 \subsection{ Limiting of the slopes within the interior} 685 \label{sec: limit}685 \label{sec:TRIADS_limit} 686 686 687 687 As discussed in \autoref{subsec:LDF_slp_iso}, … … 693 693 It is of course relevant to the iso-neutral slopes $\tilde{r}_i=r_i+\sigma_i$ relative to geopotentials 694 694 (here the $\sigma_i$ are the slopes of the coordinate surfaces relative to geopotentials) 695 \autoref{eq: PE_slopes_eiv} rather than the slope $r_i$ relative to coordinate surfaces, so we require695 \autoref{eq:MB_slopes_eiv} rather than the slope $r_i$ relative to coordinate surfaces, so we require 696 696 \[ 697 697 |\tilde{r}_i|\leq \tilde{r}_\mathrm{max}=0.01. … … 700 700 Each individual triad slope 701 701 \begin{equation} 702 \label{eq: Rtilde}702 \label{eq:TRIADS_Rtilde} 703 703 _i^k\tilde{\mathbb{R}}_{i_p}^{k_p} = {}_i^k\mathbb{R}_{i_p}^{k_p} + \frac{\delta_{i+i_p}[z_T^k]}{{e_{1u}}_{\,i + i_p}^{\,k}} 704 704 \end{equation} … … 711 711 712 712 \subsection{Tapering within the surface mixed layer} 713 \label{sec: taper}713 \label{sec:TRIADS_taper} 714 714 715 715 Additional tapering of the iso-neutral fluxes is necessary within the surface mixed layer. … … 717 717 718 718 \subsubsection{Linear slope tapering within the surface mixed layer} 719 \label{sec: lintaper}719 \label{sec:TRIADS_lintaper} 720 720 721 721 This is the option activated by the default choice \np{ln\_triad\_iso}\forcode{ = .false.}. 722 722 Slopes $\tilde{r}_i$ relative to geopotentials are tapered linearly from their value immediately below 723 the mixed layer to zero at the surface, as described in option (c) of \autoref{fig: eiv_slp}, to values724 \begin{equation} 725 \label{eq: rmtilde}723 the mixed layer to zero at the surface, as described in option (c) of \autoref{fig:LDF_eiv_slp}, to values 724 \begin{equation} 725 \label{eq:TRIADS_rmtilde} 726 726 \rMLt = -\frac{z}{h}\left.\tilde{r}_i\right|_{z=-h}\quad \text{ for } z>-h, 727 727 \end{equation} 728 728 and then the $r_i$ relative to vertical coordinate surfaces are appropriately adjusted to 729 729 \[ 730 % \label{eq: rm}730 % \label{eq:TRIADS_rm} 731 731 \rML =\rMLt -\sigma_i \quad \text{ for } z>-h. 732 732 \] 733 733 Thus the diffusion operator within the mixed layer is given by: 734 734 \[ 735 % \label{eq: iso_tensor_ML}735 % \label{eq:TRIADS_iso_tensor_ML} 736 736 D^{lT}=\nabla {\mathrm {\mathbf .}}\left( {A^{lT}\;\Re \;\nabla T} \right) \qquad 737 737 \mbox{with}\quad \;\;\Re =\left( {{ … … 747 747 in isopycnal layers immediately below, in the thermocline. 748 748 It is consistent with the way the $\tilde{r}_i$ are tapered within the mixed layer 749 (see \autoref{sec: taperskew} below) so as to ensure a uniform GM eddy-induced velocity throughout the mixed layer.749 (see \autoref{sec:TRIADS_taperskew} below) so as to ensure a uniform GM eddy-induced velocity throughout the mixed layer. 750 750 However, it gives a downwards density flux and so acts so as to reduce potential energy in the same way as 751 does the slope limiting discussed above in \autoref{sec: limit}.752 753 As in \autoref{sec: limit} above, the tapering \autoref{eq:rmtilde} is applied separately to751 does the slope limiting discussed above in \autoref{sec:TRIADS_limit}. 752 753 As in \autoref{sec:TRIADS_limit} above, the tapering \autoref{eq:TRIADS_rmtilde} is applied separately to 754 754 each triad $_i^k\tilde{\mathbb{R}}_{i_p}^{k_p}$, and the $_i^k\mathbb{R}_{i_p}^{k_p}$ adjusted. 755 755 For clarity, we assume $z$-coordinates in the following; 756 756 the conversion from $\mathbb{R}$ to $\tilde{\mathbb{R}}$ and back to $\mathbb{R}$ follows exactly as 757 described above by \autoref{eq: Rtilde}.757 described above by \autoref{eq:TRIADS_Rtilde}. 758 758 \begin{enumerate} 759 759 \item 760 760 Mixed-layer depth is defined so as to avoid including regions of weak vertical stratification in 761 761 the slope definition. 762 At each $i,j$ (simplified to $i$ in \autoref{fig: MLB_triad}),762 At each $i,j$ (simplified to $i$ in \autoref{fig:TRIADS_MLB_triad}), 763 763 we define the mixed-layer by setting the vertical index of the tracer point immediately below the mixed layer, 764 764 $k_{\mathrm{ML}}$, as the maximum $k$ (shallowest tracer point) such that 765 765 the potential density ${\rho_0}_{i,k}>{\rho_0}_{i,k_{10}}+\Delta\rho_c$, 766 766 where $i,k_{10}$ is the tracer gridbox within which the depth reaches 10~m. 767 See the left side of \autoref{fig: MLB_triad}.767 See the left side of \autoref{fig:TRIADS_MLB_triad}. 768 768 We use the $k_{10}$-gridbox instead of the surface gridbox to avoid problems \eg\ with thin daytime mixed-layers. 769 769 Currently we use the same $\Delta\rho_c=0.01\;\mathrm{kg\:m^{-3}}$ for ML triad tapering as is used to … … 776 776 This is to ensure that the vertical density gradients associated with 777 777 these basal triad slopes ${\:}_i{\mathbb{R}_{\mathrm{base}}}_{\,i_p}^{k_p}$ are representative of the thermocline. 778 The four basal triads defined in the bottom part of \autoref{fig: MLB_triad} are then778 The four basal triads defined in the bottom part of \autoref{fig:TRIADS_MLB_triad} are then 779 779 \begin{align*} 780 780 {\:}_i{\mathbb{R}_{\mathrm{base}}}_{\,i_p}^{k_p} &= 781 781 {\:}^{k_{\mathrm{ML}}-k_p-1/2}_i{\mathbb{R}_{\mathrm{base}}}_{\,i_p}^{k_p}, 782 % \label{eq: Rbase}782 % \label{eq:TRIADS_Rbase} 783 783 \\ 784 784 \intertext{with \eg\ the green triad} … … 789 789 the $w$-point $i,k_{\mathrm{ML}}-1/2$ lying \emph{below} the $i,k_{\mathrm{ML}}$ tracer point, so it is this depth 790 790 \[ 791 % \label{eq: zbase}791 % \label{eq:TRIADS_zbase} 792 792 {z_\mathrm{base}}_{\,i}={z_{w}}_{k_\mathrm{ML}-1/2} 793 793 \] 794 794 one gridbox deeper than the diagnosed ML depth $z_{\mathrm{ML}})$ that sets the $h$ used to taper the slopes in 795 \autoref{eq: rmtilde}.795 \autoref{eq:TRIADS_rmtilde}. 796 796 \item 797 797 Finally, we calculate the adjusted triads ${\:}_i^k{\mathbb{R}_{\mathrm{ML}}}_{\,i_p}^{k_p}$ within … … 805 805 {\:}_i^k{\mathbb{R}_{\mathrm{ML}}}_{\,i_p}^{k_p} &= 806 806 \frac{{z_w}_{k+k_p}}{{z_{\mathrm{base}}}_{\,i}}{\:}_i{\mathbb{R}_{\mathrm{base}}}_{\,i_p}^{k_p}. 807 % \label{eq: RML}807 % \label{eq:TRIADS_RML} 808 808 \end{align*} 809 809 \end{enumerate} … … 813 813 % \fcapside { 814 814 \caption{ 815 \protect\label{fig: MLB_triad}815 \protect\label{fig:TRIADS_MLB_triad} 816 816 Definition of mixed-layer depth and calculation of linearly tapered triads. 817 817 The figure shows a water column at a given $i,j$ (simplified to $i$), with the ocean surface at the top. … … 836 836 837 837 \subsubsection{Additional truncation of skew iso-neutral flux components} 838 \label{subsec: Gerdes-taper}838 \label{subsec:TRIADS_Gerdes-taper} 839 839 840 840 The alternative option is activated by setting \np{ln\_triad\_iso} = true. … … 843 843 but replaces the $\rML$ in the skew term by 844 844 \begin{equation} 845 \label{eq: rm*}845 \label{eq:TRIADS_rm*} 846 846 \rML^*=\left.\rMLt^2\right/\tilde{r}_i-\sigma_i, 847 847 \end{equation} 848 848 giving a ML diffusive operator 849 849 \[ 850 % \label{eq: iso_tensor_ML2}850 % \label{eq:TRIADS_iso_tensor_ML2} 851 851 D^{lT}=\nabla {\mathrm {\mathbf .}}\left( {A^{lT}\;\Re \;\nabla T} \right) \qquad 852 852 \mbox{with}\quad \;\;\Re =\left( {{ … … 881 881 % ================================================================ 882 882 \section{Eddy induced advection formulated as a skew flux} 883 \label{sec: skew-flux}883 \label{sec:TRIADS_skew-flux} 884 884 885 885 \subsection{Continuous skew flux formulation} 886 \label{sec: continuous-skew-flux}886 \label{sec:TRIADS_continuous-skew-flux} 887 887 888 888 When Gent and McWilliams's [1990] diffusion is used, an additional advection term is added. … … 890 890 the formulation of which depends on the slopes of iso-neutral surfaces. 891 891 Contrary to the case of iso-neutral mixing, the slopes used here are referenced to the geopotential surfaces, 892 \ie\ \autoref{eq: ldfslp_geo} is used in $z$-coordinate,893 and the sum \autoref{eq: ldfslp_geo} + \autoref{eq:ldfslp_iso} in $z^*$ or $s$-coordinates.892 \ie\ \autoref{eq:LDF_slp_geo} is used in $z$-coordinate, 893 and the sum \autoref{eq:LDF_slp_geo} + \autoref{eq:LDF_slp_iso} in $z^*$ or $s$-coordinates. 894 894 895 895 The eddy induced velocity is given by: 896 896 \begin{subequations} 897 % \label{eq: eiv}897 % \label{eq:TRIADS_eiv} 898 898 \begin{equation} 899 \label{eq: eiv_v}899 \label{eq:TRIADS_eiv_v} 900 900 \begin{split} 901 901 u^* & = - \frac{1}{e_{3}}\; \partial_i\psi_1, \\ … … 907 907 where the streamfunctions $\psi_i$ are given by 908 908 \begin{equation} 909 \label{eq: eiv_psi}909 \label{eq:TRIADS_eiv_psi} 910 910 \begin{split} 911 911 \psi_1 & = A_{e} \; \tilde{r}_1, \\ … … 958 958 we end up with the skew form of the eddy induced advective fluxes per unit area in $ijk$ space: 959 959 \begin{equation} 960 \label{eq: eiv_skew_ijk}960 \label{eq:TRIADS_eiv_skew_ijk} 961 961 \textbf{F}_\mathrm{eiv}^T = 962 962 \begin{pmatrix} … … 967 967 The total fluxes per unit physical area are then 968 968 \begin{equation} 969 \label{eq: eiv_skew_physical}969 \label{eq:TRIADS_eiv_skew_physical} 970 970 \begin{split} 971 971 f^*_1 & = \frac{1}{e_{3}}\; \psi_1 \partial_k T \\ … … 974 974 \end{split} 975 975 \end{equation} 976 Note that \autoref{eq: eiv_skew_physical} takes the same form whatever the vertical coordinate,977 though of course the slopes $\tilde{r}_i$ which define the $\psi_i$ in \autoref{eq: eiv_psi} are relative to976 Note that \autoref{eq:TRIADS_eiv_skew_physical} takes the same form whatever the vertical coordinate, 977 though of course the slopes $\tilde{r}_i$ which define the $\psi_i$ in \autoref{eq:TRIADS_eiv_psi} are relative to 978 978 geopotentials. 979 979 The tendency associated with eddy induced velocity is then simply the convergence of the fluxes 980 (\autoref{eq: eiv_skew_ijk}, \autoref{eq:eiv_skew_physical}), so981 \[ 982 % \label{eq: skew_eiv_conv}980 (\autoref{eq:TRIADS_eiv_skew_ijk}, \autoref{eq:TRIADS_eiv_skew_physical}), so 981 \[ 982 % \label{eq:TRIADS_skew_eiv_conv} 983 983 \frac{\partial T}{\partial t}= -\frac{1}{e_1 \, e_2 \, e_3 } \left[ 984 984 \frac{\partial}{\partial i} \left( e_2 \psi_1 \partial_k T\right) … … 993 993 \subsection{Discrete skew flux formulation} 994 994 995 The skew fluxes in (\autoref{eq: eiv_skew_physical}, \autoref{eq:eiv_skew_ijk}),996 like the off-diagonal terms (\autoref{eq: i13c}, \autoref{eq:i31c}) of the small angle diffusion tensor,997 are best expressed in terms of the triad slopes, as in \autoref{fig: ISO_triad} and998 (\autoref{eq: i13}, \autoref{eq:i31});995 The skew fluxes in (\autoref{eq:TRIADS_eiv_skew_physical}, \autoref{eq:TRIADS_eiv_skew_ijk}), 996 like the off-diagonal terms (\autoref{eq:TRIADS_i13c}, \autoref{eq:TRIADS_i31c}) of the small angle diffusion tensor, 997 are best expressed in terms of the triad slopes, as in \autoref{fig:TRIADS_ISO_triad} and 998 (\autoref{eq:TRIADS_i13}, \autoref{eq:TRIADS_i31}); 999 999 but now in terms of the triad slopes $\tilde{\mathbb{R}}$ relative to geopotentials instead of 1000 1000 the $\mathbb{R}$ relative to coordinate surfaces. 1001 The discrete form of \autoref{eq: eiv_skew_ijk} using the slopes \autoref{eq:R} and1001 The discrete form of \autoref{eq:TRIADS_eiv_skew_ijk} using the slopes \autoref{eq:TRIADS_R} and 1002 1002 defining $A_e$ at $T$-points is then given by: 1003 1003 1004 1004 \begin{subequations} 1005 % \label{eq: allskewflux}1005 % \label{eq:TRIADS_allskewflux} 1006 1006 \begin{flalign*} 1007 % \label{eq: vect_skew_flux}1007 % \label{eq:TRIADS_vect_skew_flux} 1008 1008 \vect{F}_{\mathrm{eiv}}(T) &\equiv \sum_{\substack{i_p,\,k_p}} 1009 1009 \begin{pmatrix} … … 1012 1012 \end{pmatrix}, 1013 1013 \end{flalign*} 1014 where the skew flux in the $i$-direction associated with a given triad is (\autoref{eq: latflux-triad},1015 \autoref{eq: triadfluxu}):1014 where the skew flux in the $i$-direction associated with a given triad is (\autoref{eq:TRIADS_latflux-triad}, 1015 \autoref{eq:TRIADS_triadfluxu}): 1016 1016 \begin{align} 1017 \label{eq: skewfluxu}1017 \label{eq:TRIADS_skewfluxu} 1018 1018 _i^k {\mathbb{S}_u}_{i_p}^{k_p} (T) &= + \fractext{1}{4} {A_e}_i^k{ 1019 1019 \:}\frac{{b_u}_{i+i_p}^k}{{e_{1u}}_{\,i + i_p}^{\,k}} … … 1021 1021 \frac{ \delta_{k+k_p} [T^i] }{{e_{3w}}_{\,i}^{\,k+k_p} }, \\ 1022 1022 \intertext{ 1023 and \autoref{eq: triadfluxw} in the $k$-direction, changing the sign1024 to be consistent with \autoref{eq: eiv_skew_ijk}:1023 and \autoref{eq:TRIADS_triadfluxw} in the $k$-direction, changing the sign 1024 to be consistent with \autoref{eq:TRIADS_eiv_skew_ijk}: 1025 1025 } 1026 1026 _i^k {\mathbb{S}_w}_{i_p}^{k_p} (T) 1027 1027 &= -\fractext{1}{4} {A_e}_i^k{\: }\frac{{b_u}_{i+i_p}^k}{{e_{3w}}_{\,i}^{\,k+k_p}} 1028 {_i^k\tilde{\mathbb{R}}_{i_p}^{k_p}}\frac{ \delta_{i+ i_p}[T^k] }{ {e_{1u}}_{\,i + i_p}^{\,k} }.\label{eq: skewfluxw}1028 {_i^k\tilde{\mathbb{R}}_{i_p}^{k_p}}\frac{ \delta_{i+ i_p}[T^k] }{ {e_{1u}}_{\,i + i_p}^{\,k} }.\label{eq:TRIADS_skewfluxw} 1029 1029 \end{align} 1030 1030 \end{subequations} … … 1038 1038 This can be seen %either from Appendix \autoref{apdx:eiv_skew} or 1039 1039 by considering the fluxes associated with a given triad slope $_i^k{\mathbb{R}}_{i_p}^{k_p} (T)$. 1040 For, following \autoref{subsec: variance} and \autoref{eq:dvar_iso_i},1040 For, following \autoref{subsec:TRIADS_variance} and \autoref{eq:TRIADS_dvar_iso_i}, 1041 1041 the associated horizontal skew-flux $_i^k{\mathbb{S}_u}_{i_p}^{k_p} (T)$ drives a net rate of change of variance, 1042 1042 summed over the two $T$-points $i+i_p-\fractext{1}{2},k$ and $i+i_p+\fractext{1}{2},k$, of 1043 1043 \begin{equation} 1044 \label{eq: dvar_eiv_i}1044 \label{eq:TRIADS_dvar_eiv_i} 1045 1045 _i^k{\mathbb{S}_u}_{i_p}^{k_p} (T)\,\delta_{i+ i_p}[T^k], 1046 1046 \end{equation} … … 1048 1048 the $T$-points $i,k+k_p-\fractext{1}{2}$ (above) and $i,k+k_p+\fractext{1}{2}$ (below) of 1049 1049 \begin{equation} 1050 \label{eq: dvar_eiv_k}1050 \label{eq:TRIADS_dvar_eiv_k} 1051 1051 _i^k{\mathbb{S}_w}_{i_p}^{k_p} (T) \,\delta_{k+ k_p}[T^i]. 1052 1052 \end{equation} 1053 Inspection of the definitions (\autoref{eq: skewfluxu}, \autoref{eq:skewfluxw}) shows that1054 these two variance changes (\autoref{eq: dvar_eiv_i}, \autoref{eq:dvar_eiv_k}) sum to zero.1053 Inspection of the definitions (\autoref{eq:TRIADS_skewfluxu}, \autoref{eq:TRIADS_skewfluxw}) shows that 1054 these two variance changes (\autoref{eq:TRIADS_dvar_eiv_i}, \autoref{eq:TRIADS_dvar_eiv_k}) sum to zero. 1055 1055 Hence the two fluxes associated with each triad make no net contribution to the variance budget. 1056 1056 … … 1064 1064 For the change in gravitational PE driven by the $k$-flux is 1065 1065 \begin{align} 1066 \label{eq: vert_densityPE}1066 \label{eq:TRIADS_vert_densityPE} 1067 1067 g {e_{3w}}_{\,i}^{\,k+k_p}{\mathbb{S}_w}_{i_p}^{k_p} (\rho) 1068 1068 &=g {e_{3w}}_{\,i}^{\,k+k_p}\left[-\alpha _i^k {\:}_i^k 1069 1069 {\mathbb{S}_w}_{i_p}^{k_p} (T) + \beta_i^k {\:}_i^k 1070 1070 {\mathbb{S}_w}_{i_p}^{k_p} (S) \right]. \notag \\ 1071 \intertext{Substituting ${\:}_i^k {\mathbb{S}_w}_{i_p}^{k_p}$ from \autoref{eq: skewfluxw}, gives}1071 \intertext{Substituting ${\:}_i^k {\mathbb{S}_w}_{i_p}^{k_p}$ from \autoref{eq:TRIADS_skewfluxw}, gives} 1072 1072 % and separating out 1073 1073 % $\rtriadt{R}=\rtriad{R} + \delta_{i+i_p}[z_T^k]$, … … 1080 1080 \frac{-\alpha_i^k \delta_{k+ k_p}[T^i]+ \beta_i^k\delta_{k+ k_p}[S^i]} {{e_{3w}}_{\,i}^{\,k+k_p}}, 1081 1081 \end{align} 1082 using the definition of the triad slope $\rtriad{R}$, \autoref{eq: R} to1082 using the definition of the triad slope $\rtriad{R}$, \autoref{eq:TRIADS_R} to 1083 1083 express $-\alpha _i^k\delta_{i+ i_p}[T^k]+\beta_i^k\delta_{i+ i_p}[S^k]$ in terms of 1084 1084 $-\alpha_i^k \delta_{k+ k_p}[T^i]+ \beta_i^k\delta_{k+ k_p}[S^i]$. … … 1086 1086 Where the coordinates slope, the $i$-flux gives a PE change 1087 1087 \begin{multline} 1088 \label{eq: lat_densityPE}1088 \label{eq:TRIADS_lat_densityPE} 1089 1089 g \delta_{i+i_p}[z_T^k] 1090 1090 \left[ … … 1096 1096 \frac{-\alpha_i^k \delta_{k+ k_p}[T^i]+ \beta_i^k\delta_{k+ k_p}[S^i]} {{e_{3w}}_{\,i}^{\,k+k_p}}, 1097 1097 \end{multline} 1098 (using \autoref{eq: skewfluxu}) and so the total PE change \autoref{eq:vert_densityPE} +1099 \autoref{eq: lat_densityPE} associated with the triad fluxes is1098 (using \autoref{eq:TRIADS_skewfluxu}) and so the total PE change \autoref{eq:TRIADS_vert_densityPE} + 1099 \autoref{eq:TRIADS_lat_densityPE} associated with the triad fluxes is 1100 1100 \begin{multline*} 1101 % \label{eq: tot_densityPE}1101 % \label{eq:TRIADS_tot_densityPE} 1102 1102 g{e_{3w}}_{\,i}^{\,k+k_p}{\mathbb{S}_w}_{i_p}^{k_p} (\rho) + 1103 1103 g\delta_{i+i_p}[z_T^k] {\:}_i^k {\mathbb{S}_u}_{i_p}^{k_p} (\rho) \\ … … 1110 1110 1111 1111 \subsection{Treatment of the triads at the boundaries} 1112 \label{sec: skew_bdry}1113 1114 Triad slopes \rtriadt{R} used for the calculation of the eddy-induced skew-fluxes are masked at the boundaries 1115 in exactly the same way as are the triad slopes \rtriad{R} used for the iso-neutral diffusive fluxes, 1116 as described in \autoref{sec: iso_bdry} and \autoref{fig:bdry_triads}.1117 Thus surface layer triads $\triadt{i}{1}{R}{1/2}{-1/2}$ and $\triadt{i+1}{1}{R}{-1/2}{-1/2}$ are masked, 1118 and both near bottom triad slopes $\triadt{i}{k}{R}{1/2}{1/2}$ and $\triadt{i+1}{k}{R}{-1/2}{1/2}$ are masked when 1119 either of the $i,k+1$ or $i+1,k+1$ tracer points is masked, \ie\ the $i,k+1$ $u$-point is masked. 1112 \label{sec:TRIADS_skew_bdry} 1113 1114 Triad slopes \rtriadt{R} used for the calculation of the eddy-induced skew-fluxes are masked at the boundaries 1115 in exactly the same way as are the triad slopes \rtriad{R} used for the iso-neutral diffusive fluxes, 1116 as described in \autoref{sec:TRIADS_iso_bdry} and \autoref{fig:TRIADS_bdry_triads}. 1117 Thus surface layer triads $\triadt{i}{1}{R}{1/2}{-1/2}$ and $\triadt{i+1}{1}{R}{-1/2}{-1/2}$ are masked, 1118 and both near bottom triad slopes $\triadt{i}{k}{R}{1/2}{1/2}$ and $\triadt{i+1}{k}{R}{-1/2}{1/2}$ are masked when 1119 either of the $i,k+1$ or $i+1,k+1$ tracer points is masked, \ie\ the $i,k+1$ $u$-point is masked. 1120 1120 The namelist parameter \np{ln\_botmix\_triad} has no effect on the eddy-induced skew-fluxes. 1121 1121 1122 1122 \subsection{Limiting of the slopes within the interior} 1123 \label{sec: limitskew}1124 1125 Presently, the iso-neutral slopes $\tilde{r}_i$ relative to geopotentials are limited to be less than $1/100$, 1126 exactly as in calculating the iso-neutral diffusion, \S \autoref{sec: limit}.1123 \label{sec:TRIADS_limitskew} 1124 1125 Presently, the iso-neutral slopes $\tilde{r}_i$ relative to geopotentials are limited to be less than $1/100$, 1126 exactly as in calculating the iso-neutral diffusion, \S \autoref{sec:TRIADS_limit}. 1127 1127 Each individual triad \rtriadt{R} is so limited. 1128 1128 1129 1129 \subsection{Tapering within the surface mixed layer} 1130 \label{sec: taperskew}1131 1132 The slopes $\tilde{r}_i$ relative to geopotentials (and thus the individual triads \rtriadt{R}) 1133 are always tapered linearly from their value immediately below the mixed layer to zero at the surface 1134 \autoref{eq: rmtilde}, as described in \autoref{sec:lintaper}.1135 This is option (c) of \autoref{fig: eiv_slp}.1136 This linear tapering for the slopes used to calculate the eddy-induced fluxes is unaffected by 1130 \label{sec:TRIADS_taperskew} 1131 1132 The slopes $\tilde{r}_i$ relative to geopotentials (and thus the individual triads \rtriadt{R}) 1133 are always tapered linearly from their value immediately below the mixed layer to zero at the surface 1134 \autoref{eq:TRIADS_rmtilde}, as described in \autoref{sec:TRIADS_lintaper}. 1135 This is option (c) of \autoref{fig:LDF_eiv_slp}. 1136 This linear tapering for the slopes used to calculate the eddy-induced fluxes is unaffected by 1137 1137 the value of \np{ln\_triad\_iso}. 1138 1138 … … 1140 1140 the horizontal (the most commonly used options in \NEMO: see \autoref{sec:LDF_coef}), 1141 1141 it is equivalent to a horizontal eiv (eddy-induced velocity) that is uniform within the mixed layer 1142 \autoref{eq: eiv_v}.1142 \autoref{eq:TRIADS_eiv_v}. 1143 1143 This ensures that the eiv velocities do not restratify the mixed layer \citep{treguier.held.ea_JPO97,danabasoglu.ferrari.ea_JC08}. 1144 1144 Equivantly, in terms of the skew-flux formulation we use here, … … 1148 1148 1149 1149 \subsection{Streamfunction diagnostics} 1150 \label{sec: sfdiag}1150 \label{sec:TRIADS_sfdiag} 1151 1151 1152 1152 Where the namelist parameter \np{ln\_traldf\_gdia}\forcode{ = .true.}, … … 1154 1154 Each time step, streamfunctions are calculated in the $i$-$k$ and $j$-$k$ planes at 1155 1155 $uw$ (integer +1/2 $i$, integer $j$, integer +1/2 $k$) and $vw$ (integer $i$, integer +1/2 $j$, integer +1/2 $k$) 1156 points (see Table \autoref{tab: cell}) respectively.1156 points (see Table \autoref{tab:DOM_cell}) respectively. 1157 1157 We follow \citep{griffies_bk04} and calculate the streamfunction at a given $uw$-point from 1158 1158 the surrounding four triads according to: 1159 1159 \[ 1160 % \label{eq: sfdiagi}1160 % \label{eq:TRIADS_sfdiagi} 1161 1161 {\psi_1}_{i+1/2}^{k+1/2}={\fractext{1}{4}}\sum_{\substack{i_p,\,k_p}} 1162 1162 {A_e}_{i+1/2-i_p}^{k+1/2-k_p}\:\triadd{i+1/2-i_p}{k+1/2-k_p}{R}{i_p}{k_p}. 1163 1163 \] 1164 1164 The streamfunction $\psi_1$ is calculated similarly at $vw$ points. 1165 The eddy-induced velocities are then calculated from the straightforward discretisation of \autoref{eq: eiv_v}:1166 \[ 1167 % \label{eq: eiv_v_discrete}1165 The eddy-induced velocities are then calculated from the straightforward discretisation of \autoref{eq:TRIADS_eiv_v}: 1166 \[ 1167 % \label{eq:TRIADS_eiv_v_discrete} 1168 1168 \begin{split} 1169 1169 {u^*}_{i+1/2}^{k} & = - \frac{1}{{e_{3u}}_{i}^{k}}\left({\psi_1}_{i+1/2}^{k+1/2}-{\psi_1}_{i+1/2}^{k+1/2}\right), \\ -
NEMO/trunk/doc/latex/NEMO/subfiles/chap_ASM.tex
r11537 r11543 53 53 additional tendency terms to the prognostic equations: 54 54 \begin{align*} 55 % \label{eq: wa_traj_iau}55 % \label{eq:ASM_wa_traj_iau} 56 56 {\mathbf x}^{a}(t_{i}) = M(t_{i}, t_{0})[{\mathbf x}^{b}(t_{0})] \; + \; F_{i} \delta \tilde{\mathbf x}^{a} 57 57 \end{align*} … … 66 66 The first function (namelist option \np{niaufn}=0) employs constant weights, 67 67 \begin{align} 68 \label{eq: F1_i}68 \label{eq:ASM_F1_i} 69 69 F^{(1)}_{i} 70 70 =\left\{ … … 80 80 with the weighting reduced linearly to a small value at the window end-points: 81 81 \begin{align} 82 \label{eq: F2_i}82 \label{eq:ASM_F2_i} 83 83 F^{(2)}_{i} 84 84 =\left\{ … … 92 92 \end{align} 93 93 where $\alpha^{-1} = \sum_{i=1}^{M/2} 2i$ and $M$ is assumed to be even. 94 The weights described by \autoref{eq: F2_i} provide a smoother transition of the analysis trajectory from95 one assimilation cycle to the next than that described by \autoref{eq: F1_i}.94 The weights described by \autoref{eq:ASM_F2_i} provide a smoother transition of the analysis trajectory from 95 one assimilation cycle to the next than that described by \autoref{eq:ASM_F1_i}. 96 96 97 97 %========================================================================== … … 106 106 107 107 \begin{equation} 108 \label{eq: asm_dmp}108 \label{eq:ASM_dmp} 109 109 \left\{ 110 110 \begin{aligned} … … 120 120 121 121 \[ 122 % \label{eq: asm_div}122 % \label{eq:ASM_div} 123 123 \chi^{n-1}_I = \frac{1}{e_{1t}\,e_{2t}\,e_{3t} } 124 124 \left( {\delta_i \left[ {e_{2u}\,e_{3u}\,u^{n-1}_I} \right] … … 126 126 \] 127 127 128 By the application of \autoref{eq: asm_dmp} the divergence is filtered in each iteration,128 By the application of \autoref{eq:ASM_dmp} the divergence is filtered in each iteration, 129 129 and the vorticity is left unchanged. 130 130 In the presence of coastal boundaries with zero velocity increments perpendicular to the coast -
NEMO/trunk/doc/latex/NEMO/subfiles/chap_DIA.tex
r11537 r11543 696 696 \begin{table} 697 697 \scriptsize 698 \begin{tabular x}{\textwidth}{|X|c|c|c|}698 \begin{tabular}{|l|c|c|} 699 699 \hline 700 700 tag ids affected by automatic definition of some of their attributes & 701 701 name attribute & 702 attribute value \\702 attribute value \\ 703 703 \hline 704 704 \hline 705 705 field\_definition & 706 706 freq\_op & 707 \np{rn\_rdt} \\707 \np{rn\_rdt} \\ 708 708 \hline 709 709 SBC & 710 710 freq\_op & 711 \np{rn\_rdt} $\times$ \np{nn\_fsbc} \\711 \np{rn\_rdt} $\times$ \np{nn\_fsbc} \\ 712 712 \hline 713 713 ptrc\_T & 714 714 freq\_op & 715 \np{rn\_rdt} $\times$ \np{nn\_dttrc} \\715 \np{rn\_rdt} $\times$ \np{nn\_dttrc} \\ 716 716 \hline 717 717 diad\_T & 718 718 freq\_op & 719 \np{rn\_rdt} $\times$ \np{nn\_dttrc} \\719 \np{rn\_rdt} $\times$ \np{nn\_dttrc} \\ 720 720 \hline 721 721 EqT, EqU, EqW & 722 722 jbegin, ni, & 723 according to the grid \\724 &723 according to the grid \\ 724 & 725 725 name\_suffix & 726 \\726 \\ 727 727 \hline 728 728 TAO, RAMA and PIRATA moorings & 729 729 zoom\_ibegin, zoom\_jbegin, & 730 according to the grid \\731 &730 according to the grid \\ 731 & 732 732 name\_suffix & 733 \\734 \hline 735 \end{tabular x}733 \\ 734 \hline 735 \end{tabular} 736 736 \end{table} 737 737 … … 739 739 740 740 \subsection{XML reference tables} 741 \label{subsec: IOM_xmlref}741 \label{subsec:DIA_IOM_xmlref} 742 742 743 743 \begin{enumerate} … … 1336 1336 the CF metadata standard. 1337 1337 Therefore while a user may wish to add their own metadata to the output files (as demonstrated in example 4 of 1338 section \autoref{subsec: IOM_xmlref}) the metadata should, for the most part, comply with the CF-1.5 standard.1338 section \autoref{subsec:DIA_IOM_xmlref}) the metadata should, for the most part, comply with the CF-1.5 standard. 1339 1339 1340 1340 Some metadata that may significantly increase the file size (horizontal cell areas and vertices) are controlled by … … 1407 1407 the mono-processor case (\ie\ global domain of {\small\ttfamily 182x149x31}). 1408 1408 An illustration of the potential space savings that NetCDF4 chunking and compression provides is given in 1409 table \autoref{tab: NC4} which compares the results of two short runs of the ORCA2\_LIM reference configuration with1409 table \autoref{tab:DIA_NC4} which compares the results of two short runs of the ORCA2\_LIM reference configuration with 1410 1410 a 4x2 mpi partitioning. 1411 1411 Note the variation in the compression ratio achieved which reflects chiefly the dry to wet volume ratio of … … 1447 1447 \end{tabular} 1448 1448 \caption{ 1449 \protect\label{tab: NC4}1449 \protect\label{tab:DIA_NC4} 1450 1450 Filesize comparison between NetCDF3 and NetCDF4 with chunking and compression 1451 1451 } … … 1515 1515 \section[FLO: On-Line Floats trajectories (\texttt{\textbf{key\_floats}})] 1516 1516 {FLO: On-Line Floats trajectories (\protect\key{floats})} 1517 \label{sec: FLO}1517 \label{sec:DIA_FLO} 1518 1518 %--------------------------------------------namflo------------------------------------------------------- 1519 1519 … … 1847 1847 \mathcal{V} &= \mathcal{A} \;\bar{\eta} 1848 1848 \end{split} 1849 \label{eq: MV_nBq}1849 \label{eq:DIA_MV_nBq} 1850 1850 \end{equation} 1851 1851 … … 1855 1855 \frac{1}{e_3} \partial_t ( e_3\,\rho) + \nabla( \rho \, \textbf{U} ) 1856 1856 = \left. \frac{\textit{emp}}{e_3}\right|_\textit{surface} 1857 \label{eq: Co_nBq}1857 \label{eq:DIA_Co_nBq} 1858 1858 \end{equation} 1859 1859 … … 1864 1864 \begin{equation} 1865 1865 \partial_t \mathcal{M} = \mathcal{A} \;\overline{\textit{emp}} 1866 \label{eq: Mass_nBq}1866 \label{eq:DIA_Mass_nBq} 1867 1867 \end{equation} 1868 1868 1869 1869 where $\overline{\textit{emp}} = \int_S \textit{emp}\,ds$ is the net mass flux through the ocean surface. 1870 Bringing \autoref{eq: Mass_nBq} and the time derivative of \autoref{eq:MV_nBq} together leads to1870 Bringing \autoref{eq:DIA_Mass_nBq} and the time derivative of \autoref{eq:DIA_MV_nBq} together leads to 1871 1871 the evolution equation of the mean sea level 1872 1872 … … 1874 1874 \partial_t \bar{\eta} = \frac{\overline{\textit{emp}}}{ \bar{\rho}} 1875 1875 - \frac{\mathcal{V}}{\mathcal{A}} \;\frac{\partial_t \bar{\rho} }{\bar{\rho}} 1876 \label{eq: ssh_nBq}1876 \label{eq:DIA_ssh_nBq} 1877 1877 \end{equation} 1878 1878 1879 The first term in equation \autoref{eq: ssh_nBq} alters sea level by adding or subtracting mass from the ocean.1879 The first term in equation \autoref{eq:DIA_ssh_nBq} alters sea level by adding or subtracting mass from the ocean. 1880 1880 The second term arises from temporal changes in the global mean density; \ie\ from steric effects. 1881 1881 1882 1882 In a Boussinesq fluid, $\rho$ is replaced by $\rho_o$ in all the equation except when $\rho$ appears multiplied by 1883 1883 the gravity (\ie\ in the hydrostatic balance of the primitive Equations). 1884 In particular, the mass conservation equation, \autoref{eq: Co_nBq}, degenerates into the incompressibility equation:1884 In particular, the mass conservation equation, \autoref{eq:DIA_Co_nBq}, degenerates into the incompressibility equation: 1885 1885 1886 1886 \[ 1887 1887 \frac{1}{e_3} \partial_t ( e_3 ) + \nabla( \textbf{U} ) = \left. \frac{\textit{emp}}{\rho_o \,e_3}\right|_ \textit{surface} 1888 % \label{eq: Co_Bq}1888 % \label{eq:DIA_Co_Bq} 1889 1889 \] 1890 1890 … … 1893 1893 \[ 1894 1894 \partial_t \mathcal{V} = \mathcal{A} \;\frac{\overline{\textit{emp}}}{\rho_o} 1895 % \label{eq: V_Bq}1895 % \label{eq:DIA_V_Bq} 1896 1896 \] 1897 1897 … … 1912 1912 \begin{equation} 1913 1913 \mathcal{M}_o = \mathcal{M} + \rho_o \,\eta_s \,\mathcal{A} 1914 \label{eq: M_Bq}1914 \label{eq:DIA_M_Bq} 1915 1915 \end{equation} 1916 1916 … … 1919 1919 Introducing the total density anomaly, $\mathcal{D}= \int_D d_a \,dv$, 1920 1920 where $d_a = (\rho -\rho_o ) / \rho_o$ is the density anomaly used in \NEMO\ (cf. \autoref{subsec:TRA_eos}) 1921 in \autoref{eq: M_Bq} leads to a very simple form for the steric height:1921 in \autoref{eq:DIA_M_Bq} leads to a very simple form for the steric height: 1922 1922 1923 1923 \begin{equation} 1924 1924 \eta_s = - \frac{1}{\mathcal{A}} \mathcal{D} 1925 \label{eq: steric_Bq}1925 \label{eq:DIA_steric_Bq} 1926 1926 \end{equation} 1927 1927 … … 1943 1943 (wetting and drying of grid point is not allowed). 1944 1944 1945 Third, the discretisation of \autoref{eq: steric_Bq} depends on the type of free surface which is considered.1945 Third, the discretisation of \autoref{eq:DIA_steric_Bq} depends on the type of free surface which is considered. 1946 1946 In the non linear free surface case, \ie\ \np{ln\_linssh}\forcode{=.true.}, it is given by 1947 1947 1948 1948 \[ 1949 1949 \eta_s = - \frac{ \sum_{i,\,j,\,k} d_a\; e_{1t} e_{2t} e_{3t} }{ \sum_{i,\,j,\,k} e_{1t} e_{2t} e_{3t} } 1950 % \label{eq: discrete_steric_Bq_nfs}1950 % \label{eq:DIA_discrete_steric_Bq_nfs} 1951 1951 \] 1952 1952 … … 1958 1958 \eta_s = - \frac{ \sum_{i,\,j,\,k} d_a\; e_{1t}e_{2t}e_{3t} + \sum_{i,\,j} d_a\; e_{1t}e_{2t} \eta } 1959 1959 { \sum_{i,\,j,\,k} e_{1t}e_{2t}e_{3t} + \sum_{i,\,j} e_{1t}e_{2t} \eta } 1960 % \label{eq: discrete_steric_Bq_fs}1960 % \label{eq:DIA_discrete_steric_Bq_fs} 1961 1961 \] 1962 1962 … … 1978 1978 \[ 1979 1979 \eta_s = - \frac{1}{\mathcal{A}} \int_D d_a(T,S_o,p_o) \,dv 1980 % \label{eq: thermosteric_Bq}1980 % \label{eq:DIA_thermosteric_Bq} 1981 1981 \] 1982 1982 … … 2014 2014 \includegraphics[width=\textwidth]{Fig_mask_subasins} 2015 2015 \caption{ 2016 \protect\label{fig: mask_subasins}2016 \protect\label{fig:DIA_mask_subasins} 2017 2017 Decomposition of the World Ocean (here ORCA2) into sub-basin used in to 2018 2018 compute the heat and salt transports as well as the meridional stream-function: … … 2045 2045 Pacific and Indo-Pacific Oceans (defined north of 30\deg{S}) as well as for the World Ocean. 2046 2046 The sub-basin decomposition requires an input file (\ifile{subbasins}) which contains three 2D mask arrays, 2047 the Indo-Pacific mask been deduced from the sum of the Indian and Pacific mask (\autoref{fig: mask_subasins}).2047 the Indo-Pacific mask been deduced from the sum of the Indian and Pacific mask (\autoref{fig:DIA_mask_subasins}). 2048 2048 2049 2049 %------------------------------------------namptr----------------------------------------- … … 2093 2093 \[ 2094 2094 C_u = |u|\frac{\rdt}{e_{1u}}, \quad C_v = |v|\frac{\rdt}{e_{2v}}, \quad C_w = |w|\frac{\rdt}{e_{3w}} 2095 % \label{eq: CFL}2095 % \label{eq:DIA_CFL} 2096 2096 \] 2097 2097 -
NEMO/trunk/doc/latex/NEMO/subfiles/chap_DOM.tex
r11537 r11543 29 29 {\em 30 30 Compatibility changes Major simplification has moved many of the options to external domain configuration tools. 31 (see \autoref{apdx:DOM AINcfg})31 (see \autoref{apdx:DOMCFG}) 32 32 } \\ 33 33 {\em 3.x} & {\em Rachid Benshila, Gurvan Madec \& S\'{e}bastien Masson} & … … 38 38 \newpage 39 39 40 Having defined the continuous equations in \autoref{chap: PE} and chosen a time discretisation \autoref{chap:STP},40 Having defined the continuous equations in \autoref{chap:MB} and chosen a time discretisation \autoref{chap:TD}, 41 41 we need to choose a grid for spatial discretisation and related numerical algorithms. 42 42 In the present chapter, we provide a general description of the staggered grid used in \NEMO, … … 60 60 \includegraphics[width=\textwidth]{Fig_cell} 61 61 \caption{ 62 \protect\label{fig: cell}62 \protect\label{fig:DOM_cell} 63 63 Arrangement of variables. 64 64 $t$ indicates scalar points where temperature, salinity, density, pressure and … … 76 76 The arrangement of variables is the same in all directions. 77 77 It consists of cells centred on scalar points ($t$, $S$, $p$, $\rho$) with vector points $(u, v, w)$ defined in 78 the centre of each face of the cells (\autoref{fig: cell}).78 the centre of each face of the cells (\autoref{fig:DOM_cell}). 79 79 This is the generalisation to three dimensions of the well-known ``C'' grid in Arakawa's classification 80 80 \citep{mesinger.arakawa_bk76}. … … 84 84 The ocean mesh (\ie\ the position of all the scalar and vector points) is defined by the transformation that 85 85 gives $(\lambda,\varphi,z)$ as a function of $(i,j,k)$. 86 The grid-points are located at integer or integer and a half value of $(i,j,k)$ as indicated on \autoref{tab: cell}.86 The grid-points are located at integer or integer and a half value of $(i,j,k)$ as indicated on \autoref{tab:DOM_cell}. 87 87 In all the following, subscripts $u$, $v$, $w$, $f$, $uw$, $vw$ or $fw$ indicate the position of 88 88 the grid-point where the scale factors are defined. 89 Each scale factor is defined as the local analytical value provided by \autoref{eq: scale_factors}.89 Each scale factor is defined as the local analytical value provided by \autoref{eq:MB_scale_factors}. 90 90 As a result, the mesh on which partial derivatives $\pd[]{\lambda}$, $\pd[]{\varphi}$ and 91 91 $\pd[]{z}$ are evaluated is a uniform mesh with a grid size of unity. … … 95 95 centred finite difference approximation, not from their analytical expression. 96 96 This preserves the symmetry of the discrete set of equations and therefore satisfies many of 97 the continuous properties (see \autoref{apdx: C}).97 the continuous properties (see \autoref{apdx:INVARIANTS}). 98 98 A similar, related remark can be made about the domain size: 99 99 when needed, an area, volume, or the total ocean depth must be evaluated as the product or sum of the relevant scale factors … … 123 123 \end{tabular} 124 124 \caption{ 125 \protect\label{tab: cell}125 \protect\label{tab:DOM_cell} 126 126 Location of grid-points as a function of integer or integer and a half value of the column, line or level. 127 127 This indexing is only used for the writing of the semi -discrete equations. … … 145 145 secondly, analytical transformations encourage good practice by the definition of smoothly varying grids 146 146 (rather than allowing the user to set arbitrary jumps in thickness between adjacent layers) \citep{treguier.dukowicz.ea_JGR96}. 147 An example of the effect of such a choice is shown in \autoref{fig: zgr_e3}.147 An example of the effect of such a choice is shown in \autoref{fig:DOM_zgr_e3}. 148 148 %>>>>>>>>>>>>>>>>>>>>>>>>>>>> 149 149 \begin{figure}[!t] … … 151 151 \includegraphics[width=\textwidth]{Fig_zgr_e3} 152 152 \caption{ 153 \protect\label{fig: zgr_e3}153 \protect\label{fig:DOM_zgr_e3} 154 154 Comparison of (a) traditional definitions of grid-point position and grid-size in the vertical, 155 155 and (b) analytically derived grid-point position and scale factors. … … 174 174 the midpoint between them are: 175 175 \begin{alignat*}{2} 176 % \label{eq: di_mi}176 % \label{eq:DOM_di_mi} 177 177 \delta_i [q] &= & &q (i + 1/2) - q (i - 1/2) \\ 178 178 \overline q^{\, i} &= &\big\{ &q (i + 1/2) + q (i - 1/2) \big\} / 2 … … 180 180 181 181 Similar operators are defined with respect to $i + 1/2$, $j$, $j + 1/2$, $k$, and $k + 1/2$. 182 Following \autoref{eq: PE_grad} and \autoref{eq:PE_lap}, the gradient of a variable $q$ defined at a $t$-point has182 Following \autoref{eq:MB_grad} and \autoref{eq:MB_lap}, the gradient of a variable $q$ defined at a $t$-point has 183 183 its three components defined at $u$-, $v$- and $w$-points while its Laplacian is defined at the $t$-point. 184 184 These operators have the following discrete forms in the curvilinear $s$-coordinates system: … … 198 198 \end{multline*} 199 199 200 Following \autoref{eq: PE_curl} and \autoref{eq:PE_div}, a vector $\vect A = (a_1,a_2,a_3)$ defined at200 Following \autoref{eq:MB_curl} and \autoref{eq:MB_div}, a vector $\vect A = (a_1,a_2,a_3)$ defined at 201 201 vector points $(u,v,w)$ has its three curl components defined at $vw$-, $uw$, and $f$-points, and 202 202 its divergence defined at $t$-points: … … 255 255 In other words, the adjoint of the differencing and averaging operators are $\delta_i^* = \delta_{i + 1/2}$ and 256 256 $(\overline{\cdots}^{\, i})^* = \overline{\cdots}^{\, i + 1/2}$, respectively. 257 These two properties will be used extensively in the \autoref{apdx: C} to257 These two properties will be used extensively in the \autoref{apdx:INVARIANTS} to 258 258 demonstrate integral conservative properties of the discrete formulation chosen. 259 259 … … 269 269 \includegraphics[width=\textwidth]{Fig_index_hor} 270 270 \caption{ 271 \protect\label{fig: index_hor}271 \protect\label{fig:DOM_index_hor} 272 272 Horizontal integer indexing used in the \fortran code. 273 273 The dashed area indicates the cell in which variables contained in arrays have the same $i$- and $j$-indices … … 290 290 \label{subsec:DOM_Num_Index_hor} 291 291 292 The indexing in the horizontal plane has been chosen as shown in \autoref{fig: index_hor}.292 The indexing in the horizontal plane has been chosen as shown in \autoref{fig:DOM_index_hor}. 293 293 For an increasing $i$ index ($j$ index), 294 294 the $t$-point and the eastward $u$-point (northward $v$-point) have the same index 295 (see the dashed area in \autoref{fig: index_hor}).295 (see the dashed area in \autoref{fig:DOM_index_hor}). 296 296 A $t$-point and its nearest north-east $f$-point have the same $i$-and $j$-indices. 297 297 … … 306 306 given in \autoref{subsec:DOM_cell}. 307 307 The sea surface corresponds to the $w$-level $k = 1$, which is the same index as the $t$-level just below 308 (\autoref{fig: index_vert}).308 (\autoref{fig:DOM_index_vert}). 309 309 The last $w$-level ($k = jpk$) either corresponds to or is below the ocean floor while 310 the last $t$-level is always outside the ocean domain (\autoref{fig: index_vert}).310 the last $t$-level is always outside the ocean domain (\autoref{fig:DOM_index_vert}). 311 311 Note that a $w$-point and the directly underlaying $t$-point have a common $k$ index 312 312 (\ie\ $t$-points and their nearest $w$-point neighbour in negative index direction), 313 313 in contrast to the indexing on the horizontal plane where the $t$-point has the same index as 314 314 the nearest velocity points in the positive direction of the respective horizontal axis index 315 (compare the dashed area in \autoref{fig: index_hor} and \autoref{fig:index_vert}).315 (compare the dashed area in \autoref{fig:DOM_index_hor} and \autoref{fig:DOM_index_vert}). 316 316 Since the scale factors are chosen to be strictly positive, 317 317 a \textit{minus sign} is included in the \fortran implementations of … … 324 324 \includegraphics[width=\textwidth]{Fig_index_vert} 325 325 \caption{ 326 \protect\label{fig: index_vert}326 \protect\label{fig:DOM_index_vert} 327 327 Vertical integer indexing used in the \fortran code. 328 328 Note that the $k$-axis is oriented downward. … … 363 363 the model domain itself can be altered by runtime selections. 364 364 The code previously used to perform vertical discretisation has been incorporated into an external tool 365 (\path{./tools/DOMAINcfg}) which is briefly described in \autoref{apdx:DOM AINcfg}.365 (\path{./tools/DOMAINcfg}) which is briefly described in \autoref{apdx:DOMCFG}. 366 366 367 367 The next subsections summarise the parameter and fields related to the configuration of the whole model domain. … … 418 418 The values of the geographic longitude and latitude arrays at indices $i,j$ correspond to 419 419 the analytical expressions of the longitude $\lambda$ and latitude $\varphi$ as a function of $(i,j)$, 420 evaluated at the values as specified in \autoref{tab: cell} for the respective grid-point position.420 evaluated at the values as specified in \autoref{tab:DOM_cell} for the respective grid-point position. 421 421 The calculation of the values of the horizontal scale factor arrays in general additionally involves 422 422 partial derivatives of $\lambda$ and $\varphi$ with respect to $i$ and $j$, … … 485 485 \includegraphics[width=\textwidth]{Fig_z_zps_s_sps} 486 486 \caption{ 487 \protect\label{fig: z_zps_s_sps}487 \protect\label{fig:DOM_z_zps_s_sps} 488 488 The ocean bottom as seen by the model: 489 489 (a) $z$-coordinate with full step, … … 510 510 By default a non-linear free surface is used (\np{ln\_linssh} set to \forcode{=.false.} in \nam{dom}): 511 511 the coordinate follow the time-variation of the free surface so that the transformation is time dependent: 512 $z(i,j,k,t)$ (\eg\ \autoref{fig: z_zps_s_sps}f).512 $z(i,j,k,t)$ (\eg\ \autoref{fig:DOM_z_zps_s_sps}f). 513 513 When a linear free surface is assumed (\np{ln\_linssh} set to \forcode{=.true.} in \nam{dom}), 514 514 the vertical coordinates are fixed in time, but the seawater can move up and down across the $z_0$ surface … … 527 527 \medskip 528 528 The decision on these choices must be made when the \np{cn\_domcfg} file is constructed. 529 Three main choices are offered (\autoref{fig: z_zps_s_sps}a-c):529 Three main choices are offered (\autoref{fig:DOM_z_zps_s_sps}a-c): 530 530 531 531 \begin{itemize} … … 536 536 537 537 Additionally, hybrid combinations of the three main coordinates are available: 538 $s-z$ or $s-zps$ coordinate (\autoref{fig: z_zps_s_sps}d and \autoref{fig:z_zps_s_sps}e).538 $s-z$ or $s-zps$ coordinate (\autoref{fig:DOM_z_zps_s_sps}d and \autoref{fig:DOM_z_zps_s_sps}e). 539 539 540 540 A further choice related to vertical coordinate concerns … … 678 678 \section[Initial state (\textit{istate.F90} and \textit{dtatsd.F90})] 679 679 {Initial state (\protect\mdl{istate} and \protect\mdl{dtatsd})} 680 \label{sec:D TA_tsd}680 \label{sec:DOM_DTA_tsd} 681 681 %-----------------------------------------namtsd------------------------------------------- 682 682 \nlst{namtsd} … … 697 697 Initial values for T and S are set via a user supplied \rou{usr\_def\_istate} routine contained in \mdl{userdef\_istate}. 698 698 The default version sets horizontally uniform T and profiles as used in the GYRE configuration 699 (see \autoref{sec:CFG _gyre}).699 (see \autoref{sec:CFGS_gyre}). 700 700 \end{description} 701 701 -
NEMO/trunk/doc/latex/NEMO/subfiles/chap_DYN.tex
r11537 r11543 65 65 % Horizontal divergence and relative vorticity 66 66 %-------------------------------------------------------------------------------------------------------------- 67 \subsection[Horizontal divergence and relative vorticity (\textit{divcur.F90})] 68 {Horizontal divergence and relative vorticity (\protect\mdl{divcur})} 67 \subsection[Horizontal divergence and relative vorticity (\textit{divcur.F90})]{Horizontal divergence and relative vorticity (\protect\mdl{divcur})} 69 68 \label{subsec:DYN_divcur} 70 69 71 70 The vorticity is defined at an $f$-point (\ie\ corner point) as follows: 72 71 \begin{equation} 73 \label{eq: divcur_cur}72 \label{eq:DYN_divcur_cur} 74 73 \zeta =\frac{1}{e_{1f}\,e_{2f} }\left( {\;\delta_{i+1/2} \left[ {e_{2v}\;v} \right] 75 74 -\delta_{j+1/2} \left[ {e_{1u}\;u} \right]\;} \right) … … 79 78 It is given by: 80 79 \[ 81 % \label{eq: divcur_div}80 % \label{eq:DYN_divcur_div} 82 81 \chi =\frac{1}{e_{1t}\,e_{2t}\,e_{3t} } 83 82 \left( {\delta_i \left[ {e_{2u}\,e_{3u}\,u} \right] … … 102 101 % Sea Surface Height evolution 103 102 %-------------------------------------------------------------------------------------------------------------- 104 \subsection[Horizontal divergence and relative vorticity (\textit{sshwzv.F90})] 105 {Horizontal divergence and relative vorticity (\protect\mdl{sshwzv})} 103 \subsection[Horizontal divergence and relative vorticity (\textit{sshwzv.F90})]{Horizontal divergence and relative vorticity (\protect\mdl{sshwzv})} 106 104 \label{subsec:DYN_sshwzv} 107 105 108 106 The sea surface height is given by: 109 107 \begin{equation} 110 \label{eq: dynspg_ssh}108 \label{eq:DYN_spg_ssh} 111 109 \begin{aligned} 112 110 \frac{\partial \eta }{\partial t} … … 123 121 \textit{emp} can be written as the evaporation minus precipitation, minus the river runoff. 124 122 The sea-surface height is evaluated using exactly the same time stepping scheme as 125 the tracer equation \autoref{eq: tra_nxt}:123 the tracer equation \autoref{eq:TRA_nxt}: 126 124 a leapfrog scheme in combination with an Asselin time filter, 127 \ie\ the velocity appearing in \autoref{eq: dynspg_ssh} is centred in time (\textit{now} velocity).125 \ie\ the velocity appearing in \autoref{eq:DYN_spg_ssh} is centred in time (\textit{now} velocity). 128 126 This is of paramount importance. 129 127 Replacing $T$ by the number $1$ in the tracer equation and summing over the water column must lead to … … 134 132 taking into account the change of the thickness of the levels: 135 133 \begin{equation} 136 \label{eq: wzv}134 \label{eq:DYN_wzv} 137 135 \left\{ 138 136 \begin{aligned} … … 148 146 re-orientated downward. 149 147 \gmcomment{not sure of this... to be modified with the change in emp setting} 150 In the case of a linear free surface, the time derivative in \autoref{eq: wzv} disappears.148 In the case of a linear free surface, the time derivative in \autoref{eq:DYN_wzv} disappears. 151 149 The upper boundary condition applies at a fixed level $z=0$. 152 150 The top vertical velocity is thus equal to the divergence of the barotropic transport 153 (\ie\ the first term in the right-hand-side of \autoref{eq: dynspg_ssh}).151 (\ie\ the first term in the right-hand-side of \autoref{eq:DYN_spg_ssh}). 154 152 155 153 Note also that whereas the vertical velocity has the same discrete expression in $z$- and $s$-coordinates, … … 157 155 in the second case, $w$ is the velocity normal to the $s$-surfaces. 158 156 Note also that the $k$-axis is re-orientated downwards in the \fortran code compared to 159 the indexing used in the semi-discrete equations such as \autoref{eq: wzv}157 the indexing used in the semi-discrete equations such as \autoref{eq:DYN_wzv} 160 158 (see \autoref{subsec:DOM_Num_Index_vertical}). 161 159 … … 183 181 % Vorticity term 184 182 % ------------------------------------------------------------------------------------------------------------- 185 \subsection[Vorticity term (\textit{dynvor.F90})] 186 {Vorticity term (\protect\mdl{dynvor})} 183 \subsection[Vorticity term (\textit{dynvor.F90})]{Vorticity term (\protect\mdl{dynvor})} 187 184 \label{subsec:DYN_vor} 188 185 %------------------------------------------nam_dynvor---------------------------------------------------- … … 198 195 horizontal kinetic energy for the planetary vorticity term (MIX scheme); 199 196 or conserving both the potential enstrophy of horizontally non-divergent flow and horizontal kinetic energy 200 (EEN scheme) (see \autoref{subsec: C_vorEEN}).197 (EEN scheme) (see \autoref{subsec:INVARIANTS_vorEEN}). 201 198 In the case of ENS, ENE or MIX schemes the land sea mask may be slightly modified to ensure the consistency of 202 199 vorticity term with analytical equations (\np{ln\_dynvor\_con}\forcode{=.true.}). … … 206 203 % enstrophy conserving scheme 207 204 %------------------------------------------------------------- 208 \subsubsection[Enstrophy conserving scheme (\forcode{ln_dynvor_ens=.true.})] 209 {Enstrophy conserving scheme (\protect\np{ln\_dynvor\_ens}\forcode{=.true.})} 205 \subsubsection[Enstrophy conserving scheme (\forcode{ln_dynvor_ens = .true.})]{Enstrophy conserving scheme (\protect\np{ln\_dynvor\_ens}\forcode{ = .true.})} 210 206 \label{subsec:DYN_vor_ens} 211 207 … … 216 212 It is given by: 217 213 \begin{equation} 218 \label{eq: dynvor_ens}214 \label{eq:DYN_vor_ens} 219 215 \left\{ 220 216 \begin{aligned} … … 230 226 % energy conserving scheme 231 227 %------------------------------------------------------------- 232 \subsubsection[Energy conserving scheme (\forcode{ln_dynvor_ene=.true.})] 233 {Energy conserving scheme (\protect\np{ln\_dynvor\_ene}\forcode{=.true.})} 228 \subsubsection[Energy conserving scheme (\forcode{ln_dynvor_ene = .true.})]{Energy conserving scheme (\protect\np{ln\_dynvor\_ene}\forcode{ = .true.})} 234 229 \label{subsec:DYN_vor_ene} 235 230 … … 237 232 It is given by: 238 233 \begin{equation} 239 \label{eq: dynvor_ene}234 \label{eq:DYN_vor_ene} 240 235 \left\{ 241 236 \begin{aligned} … … 251 246 % mix energy/enstrophy conserving scheme 252 247 %------------------------------------------------------------- 253 \subsubsection[Mixed energy/enstrophy conserving scheme (\forcode{ln_dynvor_mix=.true.})] 254 {Mixed energy/enstrophy conserving scheme (\protect\np{ln\_dynvor\_mix}\forcode{=.true.})} 248 \subsubsection[Mixed energy/enstrophy conserving scheme (\forcode{ln_dynvor_mix = .true.})]{Mixed energy/enstrophy conserving scheme (\protect\np{ln\_dynvor\_mix}\forcode{ = .true.})} 255 249 \label{subsec:DYN_vor_mix} 256 250 257 251 For the mixed energy/enstrophy conserving scheme (MIX scheme), a mixture of the two previous schemes is used. 258 It consists of the ENS scheme (\autoref{eq: dynvor_ens}) for the relative vorticity term,259 and of the ENE scheme (\autoref{eq: dynvor_ene}) applied to the planetary vorticity term.260 \[ 261 % \label{eq: dynvor_mix}252 It consists of the ENS scheme (\autoref{eq:DYN_vor_ens}) for the relative vorticity term, 253 and of the ENE scheme (\autoref{eq:DYN_vor_ene}) applied to the planetary vorticity term. 254 \[ 255 % \label{eq:DYN_vor_mix} 262 256 \left\{ { 263 257 \begin{aligned} … … 277 271 % energy and enstrophy conserving scheme 278 272 %------------------------------------------------------------- 279 \subsubsection[Energy and enstrophy conserving scheme (\forcode{ln_dynvor_een=.true.})] 280 {Energy and enstrophy conserving scheme (\protect\np{ln\_dynvor\_een}\forcode{=.true.})} 273 \subsubsection[Energy and enstrophy conserving scheme (\forcode{ln_dynvor_een = .true.})]{Energy and enstrophy conserving scheme (\protect\np{ln\_dynvor\_een}\forcode{ = .true.})} 281 274 \label{subsec:DYN_vor_een} 282 275 … … 297 290 The idea is to get rid of the double averaging by considering triad combinations of vorticity. 298 291 It is noteworthy that this solution is conceptually quite similar to the one proposed by 299 \citep{griffies.gnanadesikan.ea_JPO98} for the discretization of the iso-neutral diffusion operator (see \autoref{apdx: C}).292 \citep{griffies.gnanadesikan.ea_JPO98} for the discretization of the iso-neutral diffusion operator (see \autoref{apdx:INVARIANTS}). 300 293 301 294 The \citet{arakawa.hsu_MWR90} vorticity advection scheme for a single layer is modified … … 303 296 First consider the discrete expression of the potential vorticity, $q$, defined at an $f$-point: 304 297 \[ 305 % \label{eq: pot_vor}298 % \label{eq:DYN_pot_vor} 306 299 q = \frac{\zeta +f} {e_{3f} } 307 300 \] 308 where the relative vorticity is defined by (\autoref{eq: divcur_cur}),301 where the relative vorticity is defined by (\autoref{eq:DYN_divcur_cur}), 309 302 the Coriolis parameter is given by $f=2 \,\Omega \;\sin \varphi _f $ and the layer thickness at $f$-points is: 310 303 \begin{equation} 311 \label{eq: een_e3f}304 \label{eq:DYN_een_e3f} 312 305 e_{3f} = \overline{\overline {e_{3t} }} ^{\,i+1/2,j+1/2} 313 306 \end{equation} … … 326 319 % >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> 327 320 328 A key point in \autoref{eq: een_e3f} is how the averaging in the \textbf{i}- and \textbf{j}- directions is made.321 A key point in \autoref{eq:DYN_een_e3f} is how the averaging in the \textbf{i}- and \textbf{j}- directions is made. 329 322 It uses the sum of masked t-point vertical scale factor divided either by the sum of the four t-point masks 330 323 (\np{nn\_een\_e3f}\forcode{=1}), or just by $4$ (\np{nn\_een\_e3f}\forcode{=.true.}). … … 340 333 (\autoref{fig:DYN_een_triad}): 341 334 \begin{equation} 342 \label{eq: Q_triads}335 \label{eq:DYN_Q_triads} 343 336 _i^j \mathbb{Q}^{i_p}_{j_p} 344 337 = \frac{1}{12} \ \left( q^{i-i_p}_{j+j_p} + q^{i+j_p}_{j+i_p} + q^{i+i_p}_{j-j_p} \right) … … 348 341 Finally, the vorticity terms are represented as: 349 342 \begin{equation} 350 \label{eq: dynvor_een}343 \label{eq:DYN_vor_een} 351 344 \left\{ { 352 345 \begin{aligned} … … 361 354 This EEN scheme in fact combines the conservation properties of the ENS and ENE schemes. 362 355 It conserves both total energy and potential enstrophy in the limit of horizontally nondivergent flow 363 (\ie\ $\chi$=$0$) (see \autoref{subsec: C_vorEEN}).356 (\ie\ $\chi$=$0$) (see \autoref{subsec:INVARIANTS_vorEEN}). 364 357 Applied to a realistic ocean configuration, it has been shown that it leads to a significant reduction of 365 358 the noise in the vertical velocity field \citep{le-sommer.penduff.ea_OM09}. … … 371 364 % Kinetic Energy Gradient term 372 365 %-------------------------------------------------------------------------------------------------------------- 373 \subsection[Kinetic energy gradient term (\textit{dynkeg.F90})] 374 {Kinetic energy gradient term (\protect\mdl{dynkeg})} 366 \subsection[Kinetic energy gradient term (\textit{dynkeg.F90})]{Kinetic energy gradient term (\protect\mdl{dynkeg})} 375 367 \label{subsec:DYN_keg} 376 368 377 As demonstrated in \autoref{apdx: C},369 As demonstrated in \autoref{apdx:INVARIANTS}, 378 370 there is a single discrete formulation of the kinetic energy gradient term that, 379 371 together with the formulation chosen for the vertical advection (see below), 380 372 conserves the total kinetic energy: 381 373 \[ 382 % \label{eq: dynkeg}374 % \label{eq:DYN_keg} 383 375 \left\{ 384 376 \begin{aligned} … … 392 384 % Vertical advection term 393 385 %-------------------------------------------------------------------------------------------------------------- 394 \subsection[Vertical advection term (\textit{dynzad.F90})] 395 {Vertical advection term (\protect\mdl{dynzad})} 386 \subsection[Vertical advection term (\textit{dynzad.F90})]{Vertical advection term (\protect\mdl{dynzad})} 396 387 \label{subsec:DYN_zad} 397 388 … … 400 391 conserves the total kinetic energy. 401 392 Indeed, the change of KE due to the vertical advection is exactly balanced by 402 the change of KE due to the gradient of KE (see \autoref{apdx: C}).403 \[ 404 % \label{eq: dynzad}393 the change of KE due to the gradient of KE (see \autoref{apdx:INVARIANTS}). 394 \[ 395 % \label{eq:DYN_zad} 405 396 \left\{ 406 397 \begin{aligned} … … 439 430 % Coriolis plus curvature metric terms 440 431 %-------------------------------------------------------------------------------------------------------------- 441 \subsection[Coriolis plus curvature metric terms (\textit{dynvor.F90})] 442 {Coriolis plus curvature metric terms (\protect\mdl{dynvor})} 432 \subsection[Coriolis plus curvature metric terms (\textit{dynvor.F90})]{Coriolis plus curvature metric terms (\protect\mdl{dynvor})} 443 433 \label{subsec:DYN_cor_flux} 444 434 … … 447 437 It is given by: 448 438 \begin{multline*} 449 % \label{eq: dyncor_metric}439 % \label{eq:DYN_cor_metric} 450 440 f+\frac{1}{e_1 e_2 }\left( {v\frac{\partial e_2 }{\partial i} - u\frac{\partial e_1 }{\partial j}} \right) \\ 451 441 \equiv f + \frac{1}{e_{1f} e_{2f} } \left( { \ \overline v ^{i+1/2}\delta_{i+1/2} \left[ {e_{2u} } \right] … … 453 443 \end{multline*} 454 444 455 Any of the (\autoref{eq: dynvor_ens}), (\autoref{eq:dynvor_ene}) and (\autoref{eq:dynvor_een}) schemes can be used to445 Any of the (\autoref{eq:DYN_vor_ens}), (\autoref{eq:DYN_vor_ene}) and (\autoref{eq:DYN_vor_een}) schemes can be used to 456 446 compute the product of the Coriolis parameter and the vorticity. 457 However, the energy-conserving scheme (\autoref{eq: dynvor_een}) has exclusively been used to date.447 However, the energy-conserving scheme (\autoref{eq:DYN_vor_een}) has exclusively been used to date. 458 448 This term is evaluated using a leapfrog scheme, \ie\ the velocity is centred in time (\textit{now} velocity). 459 449 … … 461 451 % Flux form Advection term 462 452 %-------------------------------------------------------------------------------------------------------------- 463 \subsection[Flux form advection term (\textit{dynadv.F90})] 464 {Flux form advection term (\protect\mdl{dynadv})} 453 \subsection[Flux form advection term (\textit{dynadv.F90})]{Flux form advection term (\protect\mdl{dynadv})} 465 454 \label{subsec:DYN_adv_flux} 466 455 467 456 The discrete expression of the advection term is given by: 468 457 \[ 469 % \label{eq: dynadv}458 % \label{eq:DYN_adv} 470 459 \left\{ 471 460 \begin{aligned} … … 495 484 % 2nd order centred scheme 496 485 %------------------------------------------------------------- 497 \subsubsection[CEN2: $2^{nd}$ order centred scheme (\forcode{ln_dynadv_cen2=.true.})] 498 {CEN2: $2^{nd}$ order centred scheme (\protect\np{ln\_dynadv\_cen2}\forcode{=.true.})} 486 \subsubsection[CEN2: $2^{nd}$ order centred scheme (\forcode{ln_dynadv_cen2 = .true.})]{CEN2: $2^{nd}$ order centred scheme (\protect\np{ln\_dynadv\_cen2}\forcode{ = .true.})} 499 487 \label{subsec:DYN_adv_cen2} 500 488 501 489 In the centered $2^{nd}$ order formulation, the velocity is evaluated as the mean of the two neighbouring points: 502 490 \begin{equation} 503 \label{eq: dynadv_cen2}491 \label{eq:DYN_adv_cen2} 504 492 \left\{ 505 493 \begin{aligned} … … 519 507 % UBS scheme 520 508 %------------------------------------------------------------- 521 \subsubsection[UBS: Upstream Biased Scheme (\forcode{ln_dynadv_ubs=.true.})] 522 {UBS: Upstream Biased Scheme (\protect\np{ln\_dynadv\_ubs}\forcode{=.true.})} 509 \subsubsection[UBS: Upstream Biased Scheme (\forcode{ln_dynadv_ubs = .true.})]{UBS: Upstream Biased Scheme (\protect\np{ln\_dynadv\_ubs}\forcode{ = .true.})} 523 510 \label{subsec:DYN_adv_ubs} 524 511 … … 527 514 For example, the evaluation of $u_T^{ubs} $ is done as follows: 528 515 \begin{equation} 529 \label{eq: dynadv_ubs}516 \label{eq:DYN_adv_ubs} 530 517 u_T^{ubs} =\overline u ^i-\;\frac{1}{6} 531 518 \begin{cases} … … 547 534 The UBS scheme is not used in all directions. 548 535 In the vertical, the centred $2^{nd}$ order evaluation of the advection is preferred, \ie\ $u_{uw}^{ubs}$ and 549 $u_{vw}^{ubs}$ in \autoref{eq: dynadv_cen2} are used.536 $u_{vw}^{ubs}$ in \autoref{eq:DYN_adv_cen2} are used. 550 537 UBS is diffusive and is associated with vertical mixing of momentum. \gmcomment{ gm pursue the 551 538 sentence:Since vertical mixing of momentum is a source term of the TKE equation... } 552 539 553 For stability reasons, the first term in (\autoref{eq: dynadv_ubs}),540 For stability reasons, the first term in (\autoref{eq:DYN_adv_ubs}), 554 541 which corresponds to a second order centred scheme, is evaluated using the \textit{now} velocity (centred in time), 555 542 while the second term, which is the diffusion part of the scheme, … … 559 546 Note that the UBS and QUICK (Quadratic Upstream Interpolation for Convective Kinematics) schemes only differ by 560 547 one coefficient. 561 Replacing $1/6$ by $1/8$ in (\autoref{eq: dynadv_ubs}) leads to the QUICK advection scheme \citep{webb.de-cuevas.ea_JAOT98}.548 Replacing $1/6$ by $1/8$ in (\autoref{eq:DYN_adv_ubs}) leads to the QUICK advection scheme \citep{webb.de-cuevas.ea_JAOT98}. 562 549 This option is not available through a namelist parameter, since the $1/6$ coefficient is hard coded. 563 550 Nevertheless it is quite easy to make the substitution in the \mdl{dynadv\_ubs} module and obtain a QUICK scheme. … … 573 560 % Hydrostatic pressure gradient term 574 561 % ================================================================ 575 \section[Hydrostatic pressure gradient (\textit{dynhpg.F90})] 576 {Hydrostatic pressure gradient (\protect\mdl{dynhpg})} 562 \section[Hydrostatic pressure gradient (\textit{dynhpg.F90})]{Hydrostatic pressure gradient (\protect\mdl{dynhpg})} 577 563 \label{sec:DYN_hpg} 578 564 %------------------------------------------nam_dynhpg--------------------------------------------------- … … 596 582 % z-coordinate with full step 597 583 %-------------------------------------------------------------------------------------------------------------- 598 \subsection[Full step $Z$-coordinate (\forcode{ln_dynhpg_zco=.true.})] 599 {Full step $Z$-coordinate (\protect\np{ln\_dynhpg\_zco}\forcode{=.true.})} 584 \subsection[Full step $Z$-coordinate (\forcode{ln_dynhpg_zco = .true.})]{Full step $Z$-coordinate (\protect\np{ln\_dynhpg\_zco}\forcode{ = .true.})} 600 585 \label{subsec:DYN_hpg_zco} 601 586 … … 607 592 for $k=km$ (surface layer, $jk=1$ in the code) 608 593 \begin{equation} 609 \label{eq: dynhpg_zco_surf}594 \label{eq:DYN_hpg_zco_surf} 610 595 \left\{ 611 596 \begin{aligned} … … 620 605 for $1<k<km$ (interior layer) 621 606 \begin{equation} 622 \label{eq: dynhpg_zco}607 \label{eq:DYN_hpg_zco} 623 608 \left\{ 624 609 \begin{aligned} … … 633 618 \end{equation} 634 619 635 Note that the $1/2$ factor in (\autoref{eq: dynhpg_zco_surf}) is adequate because of the definition of $e_{3w}$ as620 Note that the $1/2$ factor in (\autoref{eq:DYN_hpg_zco_surf}) is adequate because of the definition of $e_{3w}$ as 636 621 the vertical derivative of the scale factor at the surface level ($z=0$). 637 622 Note also that in case of variable volume level (\texttt{vvl?} defined), 638 the surface pressure gradient is included in \autoref{eq: dynhpg_zco_surf} and639 \autoref{eq: dynhpg_zco} through the space and time variations of the vertical scale factor $e_{3w}$.623 the surface pressure gradient is included in \autoref{eq:DYN_hpg_zco_surf} and 624 \autoref{eq:DYN_hpg_zco} through the space and time variations of the vertical scale factor $e_{3w}$. 640 625 641 626 %-------------------------------------------------------------------------------------------------------------- 642 627 % z-coordinate with partial step 643 628 %-------------------------------------------------------------------------------------------------------------- 644 \subsection[Partial step $Z$-coordinate (\forcode{ln_dynhpg_zps=.true.})] 645 {Partial step $Z$-coordinate (\protect\np{ln\_dynhpg\_zps}\forcode{=.true.})} 629 \subsection[Partial step $Z$-coordinate (\forcode{ln_dynhpg_zps = .true.})]{Partial step $Z$-coordinate (\protect\np{ln\_dynhpg\_zps}\forcode{ = .true.})} 646 630 \label{subsec:DYN_hpg_zps} 647 631 … … 674 658 $\bullet$ Traditional coding (see for example \citet{madec.delecluse.ea_JPO96}: (\np{ln\_dynhpg\_sco}\forcode{=.true.}) 675 659 \begin{equation} 676 \label{eq: dynhpg_sco}660 \label{eq:DYN_hpg_sco} 677 661 \left\{ 678 662 \begin{aligned} … … 686 670 687 671 Where the first term is the pressure gradient along coordinates, 688 computed as in \autoref{eq: dynhpg_zco_surf} - \autoref{eq:dynhpg_zco},672 computed as in \autoref{eq:DYN_hpg_zco_surf} - \autoref{eq:DYN_hpg_zco}, 689 673 and $z_T$ is the depth of the $T$-point evaluated from the sum of the vertical scale factors at the $w$-point 690 674 ($e_{3w}$). … … 698 682 (\np{ln\_dynhpg\_djc}\forcode{=.true.}) (currently disabled; under development) 699 683 700 Note that expression \autoref{eq: dynhpg_sco} is commonly used when the variable volume formulation is activated684 Note that expression \autoref{eq:DYN_hpg_sco} is commonly used when the variable volume formulation is activated 701 685 (\texttt{vvl?}) because in that case, even with a flat bottom, 702 686 the coordinate surfaces are not horizontal but follow the free surface \citep{levier.treguier.ea_rpt07}. … … 712 696 \subsection{Ice shelf cavity} 713 697 \label{subsec:DYN_hpg_isf} 698 714 699 Beneath an ice shelf, the total pressure gradient is the sum of the pressure gradient due to the ice shelf load and 715 700 the pressure gradient due to the ocean load (\np{ln\_dynhpg\_isf}\forcode{=.true.}).\\ … … 722 707 A detailed description of this method is described in \citet{losch_JGR08}.\\ 723 708 724 The pressure gradient due to ocean load is computed using the expression \autoref{eq: dynhpg_sco} described in709 The pressure gradient due to ocean load is computed using the expression \autoref{eq:DYN_hpg_sco} described in 725 710 \autoref{subsec:DYN_hpg_sco}. 726 711 … … 728 713 % Time-scheme 729 714 %-------------------------------------------------------------------------------------------------------------- 730 \subsection[Time-scheme (\forcode{ln_dynhpg_imp={.true.,.false.}})] 731 {Time-scheme (\protect\np{ln\_dynhpg\_imp}\forcode{=.true.,.false.})} 715 \subsection[Time-scheme (\forcode{ln_dynhpg_imp = .{true,false}.})]{Time-scheme (\protect\np{ln\_dynhpg\_imp}\forcode{ = .\{true,false\}}.)} 732 716 \label{subsec:DYN_hpg_imp} 733 717 … … 748 732 749 733 \begin{equation} 750 \label{eq: dynhpg_lf}734 \label{eq:DYN_hpg_lf} 751 735 \frac{u^{t+\rdt}-u^{t-\rdt}}{2\rdt} = \;\cdots \; 752 736 -\frac{1}{\rho_o \,e_{1u} }\delta_{i+1/2} \left[ {p_h^t } \right] … … 755 739 $\bullet$ semi-implicit scheme (\np{ln\_dynhpg\_imp}\forcode{=.true.}): 756 740 \begin{equation} 757 \label{eq: dynhpg_imp}741 \label{eq:DYN_hpg_imp} 758 742 \frac{u^{t+\rdt}-u^{t-\rdt}}{2\rdt} = \;\cdots \; 759 743 -\frac{1}{4\,\rho_o \,e_{1u} } \delta_{i+1/2} \left[ p_h^{t+\rdt} +2\,p_h^t +p_h^{t-\rdt} \right] 760 744 \end{equation} 761 745 762 The semi-implicit time scheme \autoref{eq: dynhpg_imp} is made possible without746 The semi-implicit time scheme \autoref{eq:DYN_hpg_imp} is made possible without 763 747 significant additional computation since the density can be updated to time level $t+\rdt$ before 764 748 computing the horizontal hydrostatic pressure gradient. 765 749 It can be easily shown that the stability limit associated with the hydrostatic pressure gradient doubles using 766 \autoref{eq: dynhpg_imp} compared to that using the standard leapfrog scheme \autoref{eq:dynhpg_lf}.767 Note that \autoref{eq: dynhpg_imp} is equivalent to applying a time filter to the pressure gradient to750 \autoref{eq:DYN_hpg_imp} compared to that using the standard leapfrog scheme \autoref{eq:DYN_hpg_lf}. 751 Note that \autoref{eq:DYN_hpg_imp} is equivalent to applying a time filter to the pressure gradient to 768 752 eliminate high frequency IGWs. 769 Obviously, when using \autoref{eq: dynhpg_imp},753 Obviously, when using \autoref{eq:DYN_hpg_imp}, 770 754 the doubling of the time-step is achievable only if no other factors control the time-step, 771 755 such as the stability limits associated with advection or diffusion. … … 777 761 The density used to compute the hydrostatic pressure gradient (whatever the formulation) is evaluated as follows: 778 762 \[ 779 % \label{eq: rho_flt}763 % \label{eq:DYN_rho_flt} 780 764 \rho^t = \rho( \widetilde{T},\widetilde {S},z_t) 781 765 \quad \text{with} \quad … … 790 774 % Surface Pressure Gradient 791 775 % ================================================================ 792 \section[Surface pressure gradient (\textit{dynspg.F90})] 793 {Surface pressure gradient (\protect\mdl{dynspg})} 776 \section[Surface pressure gradient (\textit{dynspg.F90})]{Surface pressure gradient (\protect\mdl{dynspg})} 794 777 \label{sec:DYN_spg} 795 778 %-----------------------------------------nam_dynspg---------------------------------------------------- … … 799 782 800 783 Options are defined through the \nam{dyn\_spg} namelist variables. 801 The surface pressure gradient term is related to the representation of the free surface (\autoref{sec: PE_hor_pg}).784 The surface pressure gradient term is related to the representation of the free surface (\autoref{sec:MB_hor_pg}). 802 785 The main distinction is between the fixed volume case (linear free surface) and 803 786 the variable volume case (nonlinear free surface, \texttt{vvl?} is defined). 804 In the linear free surface case (\autoref{subsec: PE_free_surface})787 In the linear free surface case (\autoref{subsec:MB_free_surface}) 805 788 the vertical scale factors $e_{3}$ are fixed in time, 806 while they are time-dependent in the nonlinear case (\autoref{subsec: PE_free_surface}).789 while they are time-dependent in the nonlinear case (\autoref{subsec:MB_free_surface}). 807 790 With both linear and nonlinear free surface, external gravity waves are allowed in the equations, 808 791 which imposes a very small time step when an explicit time stepping is used. 809 792 Two methods are proposed to allow a longer time step for the three-dimensional equations: 810 the filtered free surface, which is a modification of the continuous equations (see \autoref{eq: PE_flt?}),793 the filtered free surface, which is a modification of the continuous equations (see \autoref{eq:MB_flt?}), 811 794 and the split-explicit free surface described below. 812 795 The extra term introduced in the filtered method is calculated implicitly, … … 815 798 816 799 The form of the surface pressure gradient term depends on how the user wants to 817 handle the fast external gravity waves that are a solution of the analytical equation (\autoref{sec: PE_hor_pg}).800 handle the fast external gravity waves that are a solution of the analytical equation (\autoref{sec:MB_hor_pg}). 818 801 Three formulations are available, all controlled by a CPP key (ln\_dynspg\_xxx): 819 802 an explicit formulation which requires a small time step; … … 829 812 % Explicit free surface formulation 830 813 %-------------------------------------------------------------------------------------------------------------- 831 \subsection[Explicit free surface (\texttt{ln\_dynspg\_exp}\forcode{=.true.})] 832 {Explicit free surface (\protect\np{ln\_dynspg\_exp}\forcode{=.true.})} 814 \subsection[Explicit free surface (\texttt{ln\_dynspg\_exp}\forcode{ = .true.})]{Explicit free surface (\protect\np{ln\_dynspg\_exp}\forcode{ = .true.})} 833 815 \label{subsec:DYN_spg_exp} 834 816 … … 839 821 is thus simply given by : 840 822 \begin{equation} 841 \label{eq: dynspg_exp}823 \label{eq:DYN_spg_exp} 842 824 \left\{ 843 825 \begin{aligned} … … 856 838 % Split-explict free surface formulation 857 839 %-------------------------------------------------------------------------------------------------------------- 858 \subsection[Split-explicit free surface (\texttt{ln\_dynspg\_ts}\forcode{=.true.})] 859 {Split-explicit free surface (\protect\np{ln\_dynspg\_ts}\forcode{=.true.})} 840 \subsection[Split-explicit free surface (\texttt{ln\_dynspg\_ts}\forcode{ = .true.})]{Split-explicit free surface (\protect\np{ln\_dynspg\_ts}\forcode{ = .true.})} 860 841 \label{subsec:DYN_spg_ts} 861 842 %------------------------------------------namsplit----------------------------------------------------------- … … 868 849 The general idea is to solve the free surface equation and the associated barotropic velocity equations with 869 850 a smaller time step than $\rdt$, the time step used for the three dimensional prognostic variables 870 (\autoref{fig:DYN_ dynspg_ts}).851 (\autoref{fig:DYN_spg_ts}). 871 852 The size of the small time step, $\rdt_e$ (the external mode or barotropic time step) is provided through 872 853 the \np{nn\_baro} namelist parameter as: $\rdt_e = \rdt / nn\_baro$. … … 879 860 The barotropic mode solves the following equations: 880 861 % \begin{subequations} 881 % \label{eq: BT}882 \begin{equation} 883 \label{eq: BT_dyn}862 % \label{eq:DYN_BT} 863 \begin{equation} 864 \label{eq:DYN_BT_dyn} 884 865 \frac{\partial {\mathrm \overline{{\mathbf U}}_h} }{\partial t}= 885 866 -f\;{\mathrm {\mathbf k}}\times {\mathrm \overline{{\mathbf U}}_h} … … 887 868 \end{equation} 888 869 \[ 889 % \label{eq: BT_ssh}870 % \label{eq:DYN_BT_ssh} 890 871 \frac{\partial \eta }{\partial t}=-\nabla \cdot \left[ {\left( {H+\eta } \right) \; {\mathrm{\mathbf \overline{U}}}_h \,} \right]+P-E 891 872 \] … … 893 874 where $\mathrm {\overline{\mathbf G}}$ is a forcing term held constant, containing coupling term between modes, 894 875 surface atmospheric forcing as well as slowly varying barotropic terms not explicitly computed to gain efficiency. 895 The third term on the right hand side of \autoref{eq: BT_dyn} represents the bottom stress896 (see section \autoref{sec:ZDF_ bfr}), explicitly accounted for at each barotropic iteration.876 The third term on the right hand side of \autoref{eq:DYN_BT_dyn} represents the bottom stress 877 (see section \autoref{sec:ZDF_drg}), explicitly accounted for at each barotropic iteration. 897 878 Temporal discretization of the system above follows a three-time step Generalized Forward Backward algorithm 898 879 detailed in \citet{shchepetkin.mcwilliams_OM05}. … … 906 887 \includegraphics[width=\textwidth]{Fig_DYN_dynspg_ts} 907 888 \caption{ 908 \protect\label{fig:DYN_ dynspg_ts}889 \protect\label{fig:DYN_spg_ts} 909 890 Schematic of the split-explicit time stepping scheme for the external and internal modes. 910 891 Time increases to the right. In this particular exemple, … … 929 910 In the default case (\np{ln\_bt\_fw}\forcode{=.true.}), 930 911 the external mode is integrated between \textit{now} and \textit{after} baroclinic time-steps 931 (\autoref{fig:DYN_ dynspg_ts}a).912 (\autoref{fig:DYN_spg_ts}a). 932 913 To avoid aliasing of fast barotropic motions into three dimensional equations, 933 914 time filtering is eventually applied on barotropic quantities (\np{ln\_bt\_av}\forcode{=.true.}). … … 1101 1082 % Filtered free surface formulation 1102 1083 %-------------------------------------------------------------------------------------------------------------- 1103 \subsection[Filtered free surface (\texttt{dynspg\_flt?})] 1104 {Filtered free surface (\protect\texttt{dynspg\_flt?})} 1084 \subsection[Filtered free surface (\texttt{dynspg\_flt?})]{Filtered free surface (\protect\texttt{dynspg\_flt?})} 1105 1085 \label{subsec:DYN_spg_fltp} 1106 1086 1107 1087 The filtered formulation follows the \citet{roullet.madec_JGR00} implementation. 1108 The extra term introduced in the equations (see \autoref{subsec: PE_free_surface}) is solved implicitly.1088 The extra term introduced in the equations (see \autoref{subsec:MB_free_surface}) is solved implicitly. 1109 1089 The elliptic solvers available in the code are documented in \autoref{chap:MISC}. 1110 1090 … … 1112 1092 \gmcomment{ %%% copy from chap-model basics 1113 1093 \[ 1114 % \label{eq: spg_flt}1094 % \label{eq:DYN_spg_flt} 1115 1095 \frac{\partial {\mathrm {\mathbf U}}_h }{\partial t}= {\mathrm {\mathbf M}} 1116 1096 - g \nabla \left( \tilde{\rho} \ \eta \right) … … 1120 1100 $\widetilde{\rho} = \rho / \rho_o$ is the dimensionless density, 1121 1101 and $\mathrm {\mathbf M}$ represents the collected contributions of the Coriolis, hydrostatic pressure gradient, 1122 non-linear and viscous terms in \autoref{eq: PE_dyn}.1102 non-linear and viscous terms in \autoref{eq:MB_dyn}. 1123 1103 } %end gmcomment 1124 1104 … … 1130 1110 % Lateral diffusion term 1131 1111 % ================================================================ 1132 \section[Lateral diffusion term and operators (\textit{dynldf.F90})] 1133 {Lateral diffusion term and operators (\protect\mdl{dynldf})} 1112 \section[Lateral diffusion term and operators (\textit{dynldf.F90})]{Lateral diffusion term and operators (\protect\mdl{dynldf})} 1134 1113 \label{sec:DYN_ldf} 1135 1114 %------------------------------------------nam_dynldf---------------------------------------------------- … … 1145 1124 \ie\ the velocity appearing in its expression is the \textit{before} velocity in time, 1146 1125 except for the pure vertical component that appears when a tensor of rotation is used. 1147 This latter term is solved implicitly together with the vertical diffusion term (see \autoref{chap: STP}).1126 This latter term is solved implicitly together with the vertical diffusion term (see \autoref{chap:TD}). 1148 1127 1149 1128 At the lateral boundaries either free slip, … … 1165 1144 1166 1145 % ================================================================ 1167 \subsection[Iso-level laplacian (\forcode{ln_dynldf_lap=.true.})] 1168 {Iso-level laplacian operator (\protect\np{ln\_dynldf\_lap}\forcode{=.true.})} 1146 \subsection[Iso-level laplacian (\forcode{ln_dynldf_lap = .true.})]{Iso-level laplacian operator (\protect\np{ln\_dynldf\_lap}\forcode{ = .true.})} 1169 1147 \label{subsec:DYN_ldf_lap} 1170 1148 1171 1149 For lateral iso-level diffusion, the discrete operator is: 1172 1150 \begin{equation} 1173 \label{eq: dynldf_lap}1151 \label{eq:DYN_ldf_lap} 1174 1152 \left\{ 1175 1153 \begin{aligned} … … 1184 1162 \end{equation} 1185 1163 1186 As explained in \autoref{subsec: PE_ldf},1164 As explained in \autoref{subsec:MB_ldf}, 1187 1165 this formulation (as the gradient of a divergence and curl of the vorticity) preserves symmetry and 1188 1166 ensures a complete separation between the vorticity and divergence parts of the momentum diffusion. … … 1191 1169 % Rotated laplacian operator 1192 1170 %-------------------------------------------------------------------------------------------------------------- 1193 \subsection[Rotated laplacian (\forcode{ln_dynldf_iso=.true.})] 1194 {Rotated laplacian operator (\protect\np{ln\_dynldf\_iso}\forcode{=.true.})} 1171 \subsection[Rotated laplacian (\forcode{ln_dynldf_iso = .true.})]{Rotated laplacian operator (\protect\np{ln\_dynldf\_iso}\forcode{ = .true.})} 1195 1172 \label{subsec:DYN_ldf_iso} 1196 1173 … … 1206 1183 The resulting discrete representation is: 1207 1184 \begin{equation} 1208 \label{eq: dyn_ldf_iso}1185 \label{eq:DYN_ldf_iso} 1209 1186 \begin{split} 1210 1187 D_u^{l\textbf{U}} &= \frac{1}{e_{1u} \, e_{2u} \, e_{3u} } \\ … … 1250 1227 % Iso-level bilaplacian operator 1251 1228 %-------------------------------------------------------------------------------------------------------------- 1252 \subsection[Iso-level bilaplacian (\forcode{ln_dynldf_bilap=.true.})] 1253 {Iso-level bilaplacian operator (\protect\np{ln\_dynldf\_bilap}\forcode{=.true.})} 1229 \subsection[Iso-level bilaplacian (\forcode{ln_dynldf_bilap = .true.})]{Iso-level bilaplacian operator (\protect\np{ln\_dynldf\_bilap}\forcode{ = .true.})} 1254 1230 \label{subsec:DYN_ldf_bilap} 1255 1231 1256 The lateral fourth order operator formulation on momentum is obtained by applying \autoref{eq: dynldf_lap} twice.1232 The lateral fourth order operator formulation on momentum is obtained by applying \autoref{eq:DYN_ldf_lap} twice. 1257 1233 It requires an additional assumption on boundary conditions: 1258 1234 the first derivative term normal to the coast depends on the free or no-slip lateral boundary conditions chosen, … … 1265 1241 % Vertical diffusion term 1266 1242 % ================================================================ 1267 \section[Vertical diffusion term (\textit{dynzdf.F90})] 1268 {Vertical diffusion term (\protect\mdl{dynzdf})} 1243 \section[Vertical diffusion term (\textit{dynzdf.F90})]{Vertical diffusion term (\protect\mdl{dynzdf})} 1269 1244 \label{sec:DYN_zdf} 1270 1245 %----------------------------------------------namzdf------------------------------------------------------ … … 1279 1254 (\np{ln\_zdfexp}\forcode{=.true.}) using a time splitting technique (\np{nn\_zdfexp} $>$ 1) or 1280 1255 $(b)$ a backward (or implicit) time differencing scheme (\np{ln\_zdfexp}\forcode{=.false.}) 1281 (see \autoref{chap: STP}).1256 (see \autoref{chap:TD}). 1282 1257 Note that namelist variables \np{ln\_zdfexp} and \np{nn\_zdfexp} apply to both tracers and dynamics. 1283 1258 1284 1259 The formulation of the vertical subgrid scale physics is the same whatever the vertical coordinate is. 1285 The vertical diffusion operators given by \autoref{eq: PE_zdf} take the following semi-discrete space form:1286 \[ 1287 % \label{eq: dynzdf}1260 The vertical diffusion operators given by \autoref{eq:MB_zdf} take the following semi-discrete space form: 1261 \[ 1262 % \label{eq:DYN_zdf} 1288 1263 \left\{ 1289 1264 \begin{aligned} … … 1303 1278 the vertical turbulent momentum fluxes, 1304 1279 \begin{equation} 1305 \label{eq: dynzdf_sbc}1280 \label{eq:DYN_zdf_sbc} 1306 1281 \left.{\left( {\frac{A^{vm} }{e_3 }\ \frac{\partial \textbf{U}_h}{\partial k}} \right)} \right|_{z=1} 1307 1282 = \frac{1}{\rho_o} \binom{\tau_u}{\tau_v } … … 1316 1291 1317 1292 The turbulent flux of momentum at the bottom of the ocean is specified through a bottom friction parameterisation 1318 (see \autoref{sec:ZDF_ bfr})1293 (see \autoref{sec:ZDF_drg}) 1319 1294 1320 1295 % ================================================================ … … 1347 1322 \section{Wetting and drying } 1348 1323 \label{sec:DYN_wetdry} 1324 1349 1325 There are two main options for wetting and drying code (wd): 1350 1326 (a) an iterative limiter (il) and (b) a directional limiter (dl). … … 1395 1371 % Iterative limiters 1396 1372 %----------------------------------------------------------------------------------------- 1397 \subsection[Directional limiter (\textit{wet\_dry.F90})] 1398 {Directional limiter (\mdl{wet\_dry})} 1373 \subsection[Directional limiter (\textit{wet\_dry.F90})]{Directional limiter (\mdl{wet\_dry})} 1399 1374 \label{subsec:DYN_wd_directional_limiter} 1375 1400 1376 The principal idea of the directional limiter is that 1401 1377 water should not be allowed to flow out of a dry tracer cell (i.e. one whose water depth is less than \np{rn\_wdmin1}). … … 1435 1411 %----------------------------------------------------------------------------------------- 1436 1412 1437 \subsection[Iterative limiter (\textit{wet\_dry.F90})] 1438 {Iterative limiter (\mdl{wet\_dry})} 1413 \subsection[Iterative limiter (\textit{wet\_dry.F90})]{Iterative limiter (\mdl{wet\_dry})} 1439 1414 \label{subsec:DYN_wd_iterative_limiter} 1440 1415 1441 \subsubsection[Iterative flux limiter (\textit{wet\_dry.F90})] 1442 {Iterative flux limiter (\mdl{wet\_dry})} 1443 \label{subsubsec:DYN_wd_il_spg_limiter} 1416 \subsubsection[Iterative flux limiter (\textit{wet\_dry.F90})]{Iterative flux limiter (\mdl{wet\_dry})} 1417 \label{subsec:DYN_wd_il_spg_limiter} 1444 1418 1445 1419 The iterative limiter modifies the fluxes across the faces of cells that are either already ``dry'' … … 1449 1423 1450 1424 The continuity equation for the total water depth in a column 1451 \begin{equation} \label{dyn_wd_continuity} 1452 \frac{\partial h}{\partial t} + \mathbf{\nabla.}(h\mathbf{u}) = 0 . 1425 \begin{equation} 1426 \label{eq:DYN_wd_continuity} 1427 \frac{\partial h}{\partial t} + \mathbf{\nabla.}(h\mathbf{u}) = 0 . 1453 1428 \end{equation} 1454 1429 can be written in discrete form as 1455 1430 1456 \begin{align} \label{dyn_wd_continuity_2} 1457 \frac{e_1 e_2}{\Delta t} ( h_{i,j}(t_{n+1}) - h_{i,j}(t_e) ) 1458 &= - ( \mathrm{flxu}_{i+1,j} - \mathrm{flxu}_{i,j} + \mathrm{flxv}_{i,j+1} - \mathrm{flxv}_{i,j} ) \\ 1459 &= \mathrm{zzflx}_{i,j} . 1431 \begin{align} 1432 \label{eq:DYN_wd_continuity_2} 1433 \frac{e_1 e_2}{\Delta t} ( h_{i,j}(t_{n+1}) - h_{i,j}(t_e) ) 1434 &= - ( \mathrm{flxu}_{i+1,j} - \mathrm{flxu}_{i,j} + \mathrm{flxv}_{i,j+1} - \mathrm{flxv}_{i,j} ) \\ 1435 &= \mathrm{zzflx}_{i,j} . 1460 1436 \end{align} 1461 1437 … … 1470 1446 (zzflxp) and fluxes that are into the cell (zzflxn). Clearly 1471 1447 1472 \begin{equation} \label{dyn_wd_zzflx_p_n_1} 1473 \mathrm{zzflx}_{i,j} = \mathrm{zzflxp}_{i,j} + \mathrm{zzflxn}_{i,j} . 1448 \begin{equation} 1449 \label{eq:DYN_wd_zzflx_p_n_1} 1450 \mathrm{zzflx}_{i,j} = \mathrm{zzflxp}_{i,j} + \mathrm{zzflxn}_{i,j} . 1474 1451 \end{equation} 1475 1452 … … 1482 1459 $\mathrm{zcoef}_{i,j}^{(m)}$ such that: 1483 1460 1484 \begin{equation} \label{dyn_wd_continuity_coef} 1485 \begin{split} 1486 \mathrm{zzflxp}^{(m)}_{i,j} =& \mathrm{zcoef}_{i,j}^{(m)} \mathrm{zzflxp}^{(0)}_{i,j} \\ 1487 \mathrm{zzflxn}^{(m)}_{i,j} =& \mathrm{zcoef}_{i,j}^{(m)} \mathrm{zzflxn}^{(0)}_{i,j} 1488 \end{split} 1461 \begin{equation} 1462 \label{eq:DYN_wd_continuity_coef} 1463 \begin{split} 1464 \mathrm{zzflxp}^{(m)}_{i,j} =& \mathrm{zcoef}_{i,j}^{(m)} \mathrm{zzflxp}^{(0)}_{i,j} \\ 1465 \mathrm{zzflxn}^{(m)}_{i,j} =& \mathrm{zcoef}_{i,j}^{(m)} \mathrm{zzflxn}^{(0)}_{i,j} 1466 \end{split} 1489 1467 \end{equation} 1490 1468 … … 1494 1472 The iteration is initialised by setting 1495 1473 1496 \begin{equation} \label{dyn_wd_zzflx_initial} 1497 \mathrm{zzflxp^{(0)}}_{i,j} = \mathrm{zzflxp}_{i,j} , \quad \mathrm{zzflxn^{(0)}}_{i,j} = \mathrm{zzflxn}_{i,j} . 1474 \begin{equation} 1475 \label{eq:DYN_wd_zzflx_initial} 1476 \mathrm{zzflxp^{(0)}}_{i,j} = \mathrm{zzflxp}_{i,j} , \quad \mathrm{zzflxn^{(0)}}_{i,j} = \mathrm{zzflxn}_{i,j} . 1498 1477 \end{equation} 1499 1478 1500 1479 The fluxes out of cell $(i,j)$ are updated at the $m+1$th iteration if the depth of the 1501 1480 cell on timestep $t_e$, namely $h_{i,j}(t_e)$, is less than the total flux out of the cell 1502 times the timestep divided by the cell area. Using (\ ref{dyn_wd_continuity_2}) this1481 times the timestep divided by the cell area. Using (\autoref{eq:DYN_wd_continuity_2}) this 1503 1482 condition is 1504 1483 1505 \begin{equation} \label{dyn_wd_continuity_if} 1506 h_{i,j}(t_e) - \mathrm{rn\_wdmin1} < \frac{\Delta t}{e_1 e_2} ( \mathrm{zzflxp}^{(m)}_{i,j} + \mathrm{zzflxn}^{(m)}_{i,j} ) . 1507 \end{equation} 1508 1509 Rearranging (\ref{dyn_wd_continuity_if}) we can obtain an expression for the maximum 1484 \begin{equation} 1485 \label{eq:DYN_wd_continuity_if} 1486 h_{i,j}(t_e) - \mathrm{rn\_wdmin1} < \frac{\Delta t}{e_1 e_2} ( \mathrm{zzflxp}^{(m)}_{i,j} + \mathrm{zzflxn}^{(m)}_{i,j} ) . 1487 \end{equation} 1488 1489 Rearranging (\autoref{eq:DYN_wd_continuity_if}) we can obtain an expression for the maximum 1510 1490 outward flux that can be allowed and still maintain the minimum wet depth: 1511 1491 1512 \begin{equation} \label{dyn_wd_max_flux} 1513 \begin{split} 1514 \mathrm{zzflxp}^{(m+1)}_{i,j} = \Big[ (h_{i,j}(t_e) & - \mathrm{rn\_wdmin1} - \mathrm{rn\_wdmin2}) \frac{e_1 e_2}{\Delta t} \phantom{]} \\ 1515 \phantom{[} & - \mathrm{zzflxn}^{(m)}_{i,j} \Big] 1516 \end{split} 1492 \begin{equation} 1493 \label{eq:DYN_wd_max_flux} 1494 \begin{split} 1495 \mathrm{zzflxp}^{(m+1)}_{i,j} = \Big[ (h_{i,j}(t_e) & - \mathrm{rn\_wdmin1} - \mathrm{rn\_wdmin2}) \frac{e_1 e_2}{\Delta t} \phantom{]} \\ 1496 \phantom{[} & - \mathrm{zzflxn}^{(m)}_{i,j} \Big] 1497 \end{split} 1517 1498 \end{equation} 1518 1499 1519 1500 Note a small tolerance ($\mathrm{rn\_wdmin2}$) has been introduced here {\itshape [Q: Why is 1520 this necessary/desirable?]}. Substituting from (\ ref{dyn_wd_continuity_coef}) gives an1501 this necessary/desirable?]}. Substituting from (\autoref{eq:DYN_wd_continuity_coef}) gives an 1521 1502 expression for the coefficient needed to multiply the outward flux at this cell in order 1522 1503 to avoid drying. 1523 1504 1524 \begin{equation} \label{dyn_wd_continuity_nxtcoef} 1525 \begin{split} 1526 \mathrm{zcoef}^{(m+1)}_{i,j} = \Big[ (h_{i,j}(t_e) & - \mathrm{rn\_wdmin1} - \mathrm{rn\_wdmin2}) \frac{e_1 e_2}{\Delta t} \phantom{]} \\ 1527 \phantom{[} & - \mathrm{zzflxn}^{(m)}_{i,j} \Big] \frac{1}{ \mathrm{zzflxp}^{(0)}_{i,j} } 1528 \end{split} 1505 \begin{equation} 1506 \label{eq:DYN_wd_continuity_nxtcoef} 1507 \begin{split} 1508 \mathrm{zcoef}^{(m+1)}_{i,j} = \Big[ (h_{i,j}(t_e) & - \mathrm{rn\_wdmin1} - \mathrm{rn\_wdmin2}) \frac{e_1 e_2}{\Delta t} \phantom{]} \\ 1509 \phantom{[} & - \mathrm{zzflxn}^{(m)}_{i,j} \Big] \frac{1}{ \mathrm{zzflxp}^{(0)}_{i,j} } 1510 \end{split} 1529 1511 \end{equation} 1530 1512 … … 1545 1527 % Surface pressure gradients 1546 1528 %---------------------------------------------------------------------------------------- 1547 \subsubsection[Modification of surface pressure gradients (\textit{dynhpg.F90})] 1548 {Modification of surface pressure gradients (\mdl{dynhpg})} 1549 \label{subsubsec:DYN_wd_il_spg} 1529 \subsubsection[Modification of surface pressure gradients (\textit{dynhpg.F90})]{Modification of surface pressure gradients (\mdl{dynhpg})} 1530 \label{subsec:DYN_wd_il_spg} 1550 1531 1551 1532 At ``dry'' points the water depth is usually close to $\mathrm{rn\_wdmin1}$. If the … … 1560 1541 neighbouring $(i+1,j)$ and $(i,j)$ tracer points. zcpx is calculated using two logicals 1561 1542 variables, $\mathrm{ll\_tmp1}$ and $\mathrm{ll\_tmp2}$ which are evaluated for each grid 1562 column. The three possible combinations are illustrated in figure \ ref{Fig_WAD_dynhpg}.1543 column. The three possible combinations are illustrated in figure \autoref{fig:DYN_WAD_dynhpg}. 1563 1544 1564 1545 %>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> 1565 1546 \begin{figure}[!ht] \begin{center} 1566 1547 \includegraphics[width=\textwidth]{Fig_WAD_dynhpg} 1567 \caption{ \label{Fig_WAD_dynhpg} 1568 Illustrations of the three possible combinations of the logical variables controlling the 1569 limiting of the horizontal pressure gradient in wetting and drying regimes} 1570 \end{center}\end{figure} 1548 \caption{ 1549 \label{fig:DYN_WAD_dynhpg} 1550 Illustrations of the three possible combinations of the logical variables controlling the 1551 limiting of the horizontal pressure gradient in wetting and drying regimes} 1552 \end{center} 1553 \end{figure} 1571 1554 %>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> 1572 1555 … … 1576 1559 of the topography at the two points: 1577 1560 1578 \begin{equation} \label{dyn_ll_tmp1} 1579 \begin{split} 1580 \mathrm{ll\_tmp1} = & \mathrm{MIN(sshn(ji,jj), sshn(ji+1,jj))} > \\ 1561 \begin{equation} 1562 \label{eq:DYN_ll_tmp1} 1563 \begin{split} 1564 \mathrm{ll\_tmp1} = & \mathrm{MIN(sshn(ji,jj), sshn(ji+1,jj))} > \\ 1581 1565 & \quad \mathrm{MAX(-ht\_wd(ji,jj), -ht\_wd(ji+1,jj))\ .and.} \\ 1582 & \mathrm{MAX(sshn(ji,jj) + ht\_wd(ji,jj),} \\1583 & \mathrm{\phantom{MAX(}sshn(ji+1,jj) + ht\_wd(ji+1,jj))} >\\1584 & \quad\quad\mathrm{rn\_wdmin1 + rn\_wdmin2 }1585 \end{split}1566 & \mathrm{MAX(sshn(ji,jj) + ht\_wd(ji,jj),} \\ 1567 & \mathrm{\phantom{MAX(}sshn(ji+1,jj) + ht\_wd(ji+1,jj))} >\\ 1568 & \quad\quad\mathrm{rn\_wdmin1 + rn\_wdmin2 } 1569 \end{split} 1586 1570 \end{equation} 1587 1571 … … 1590 1574 at the two points plus $\mathrm{rn\_wdmin1} + \mathrm{rn\_wdmin2}$ 1591 1575 1592 \begin{equation} \label{dyn_ll_tmp2} 1593 \begin{split} 1594 \mathrm{ ll\_tmp2 } = & \mathrm{( ABS( sshn(ji,jj) - sshn(ji+1,jj) ) > 1.E-12 )\ .AND.}\\ 1595 & \mathrm{( MAX(sshn(ji,jj), sshn(ji+1,jj)) > } \\ 1596 & \mathrm{\phantom{(} MAX(-ht\_wd(ji,jj), -ht\_wd(ji+1,jj)) + rn\_wdmin1 + rn\_wdmin2}) . 1597 \end{split} 1576 \begin{equation} 1577 \label{eq:DYN_ll_tmp2} 1578 \begin{split} 1579 \mathrm{ ll\_tmp2 } = & \mathrm{( ABS( sshn(ji,jj) - sshn(ji+1,jj) ) > 1.E-12 )\ .AND.}\\ 1580 & \mathrm{( MAX(sshn(ji,jj), sshn(ji+1,jj)) > } \\ 1581 & \mathrm{\phantom{(} MAX(-ht\_wd(ji,jj), -ht\_wd(ji+1,jj)) + rn\_wdmin1 + rn\_wdmin2}) . 1582 \end{split} 1598 1583 \end{equation} 1599 1584 … … 1611 1596 conditions. 1612 1597 1613 \subsubsection[Additional considerations (\textit{usrdef\_zgr.F90})] 1614 {Additional considerations (\mdl{usrdef\_zgr})} 1615 \label{subsubsec:WAD_additional} 1598 \subsubsection[Additional considerations (\textit{usrdef\_zgr.F90})]{Additional considerations (\mdl{usrdef\_zgr})} 1599 \label{subsec:DYN_WAD_additional} 1616 1600 1617 1601 In the very shallow water where wetting and drying occurs the parametrisation of … … 1626 1610 % The WAD test cases 1627 1611 %---------------------------------------------------------------------------------------- 1628 \subsection[The WAD test cases (\textit{usrdef\_zgr.F90})] 1629 {The WAD test cases (\mdl{usrdef\_zgr})} 1630 \label{WAD_test_cases} 1612 \subsection[The WAD test cases (\textit{usrdef\_zgr.F90})]{The WAD test cases (\mdl{usrdef\_zgr})} 1613 \label{subsec:DYN_WAD_test_cases} 1631 1614 1632 1615 See the WAD tests MY\_DOC documention for details of the WAD test cases. … … 1637 1620 % Time evolution term 1638 1621 % ================================================================ 1639 \section[Time evolution term (\textit{dynnxt.F90})] 1640 {Time evolution term (\protect\mdl{dynnxt})} 1622 \section[Time evolution term (\textit{dynnxt.F90})]{Time evolution term (\protect\mdl{dynnxt})} 1641 1623 \label{sec:DYN_nxt} 1642 1624 … … 1648 1630 Options are defined through the \nam{dom} namelist variables. 1649 1631 The general framework for dynamics time stepping is a leap-frog scheme, 1650 \ie\ a three level centred time scheme associated with an Asselin time filter (cf. \autoref{chap: STP}).1632 \ie\ a three level centred time scheme associated with an Asselin time filter (cf. \autoref{chap:TD}). 1651 1633 The scheme is applied to the velocity, except when 1652 1634 using the flux form of momentum advection (cf. \autoref{sec:DYN_adv_cor_flux}) 1653 1635 in the variable volume case (\texttt{vvl?} defined), 1654 where it has to be applied to the thickness weighted velocity (see \autoref{sec: A_momentum})1636 where it has to be applied to the thickness weighted velocity (see \autoref{sec:SCOORD_momentum}) 1655 1637 1656 1638 $\bullet$ vector invariant form or linear free surface 1657 1639 (\np{ln\_dynhpg\_vec}\forcode{=.true.} ; \texttt{vvl?} not defined): 1658 1640 \[ 1659 % \label{eq: dynnxt_vec}1641 % \label{eq:DYN_nxt_vec} 1660 1642 \left\{ 1661 1643 \begin{aligned} … … 1669 1651 (\np{ln\_dynhpg\_vec}\forcode{=.false.} ; \texttt{vvl?} defined): 1670 1652 \[ 1671 % \label{eq: dynnxt_flux}1653 % \label{eq:DYN_nxt_flux} 1672 1654 \left\{ 1673 1655 \begin{aligned} -
NEMO/trunk/doc/latex/NEMO/subfiles/chap_LBC.tex
r11537 r11543 57 57 58 58 \[ 59 % \label{eq: lbc_aaaa}59 % \label{eq:LBC_aaaa} 60 60 \frac{A^{lT} }{e_1 }\frac{\partial T}{\partial i}\equiv \frac{A_u^{lT} 61 61 }{e_{1u} } \; \delta_{i+1 / 2} \left[ T \right]\;\;mask_u … … 134 134 the no-slip boundary condition, simply by multiplying it by the mask$_{f}$ : 135 135 \[ 136 % \label{eq: lbc_bbbb}136 % \label{eq:LBC_bbbb} 137 137 \zeta \equiv \frac{1}{e_{1f} {\kern 1pt}e_{2f} }\left( {\delta_{i+1/2} 138 138 \left[ {e_{2v} \,v} \right]-\delta_{j+1/2} \left[ {e_{1u} \,u} \right]} … … 226 226 The north fold boundary condition has been introduced in order to handle the north boundary of 227 227 a three-polar ORCA grid. 228 Such a grid has two poles in the northern hemisphere (\autoref{fig: MISC_ORCA_msh},229 and thus requires a specific treatment illustrated in \autoref{fig: North_Fold_T}.228 Such a grid has two poles in the northern hemisphere (\autoref{fig:CFGS_ORCA_msh}, 229 and thus requires a specific treatment illustrated in \autoref{fig:LBC_North_Fold_T}. 230 230 Further information can be found in \mdl{lbcnfd} module which applies the north fold boundary condition. 231 231 … … 235 235 \includegraphics[width=\textwidth]{Fig_North_Fold_T} 236 236 \caption{ 237 \protect\label{fig: North_Fold_T}237 \protect\label{fig:LBC_North_Fold_T} 238 238 North fold boundary with a $T$-point pivot and cyclic east-west boundary condition ($jperio=4$), 239 239 as used in ORCA 2, 1/4, and 1/12. … … 256 256 %----------------------------------------------------------------------------------------------- 257 257 258 For massively parallel processing (mpp), a domain decomposition method is used. The basic idea of the method is to split the large computation domain of a numerical experiment into several smaller domains and solve the set of equations by addressing independent local problems. Each processor has its own local memory and computes the model equation over a subdomain of the whole model domain. The subdomain boundary conditions are specified through communications between processors which are organized by explicit statements (message passing method). The present implementation is largely inspired by Guyon's work [Guyon 1995]. 258 For massively parallel processing (mpp), a domain decomposition method is used. 259 The basic idea of the method is to split the large computation domain of a numerical experiment into several smaller domains and 260 solve the set of equations by addressing independent local problems. 261 Each processor has its own local memory and computes the model equation over a subdomain of the whole model domain. 262 The subdomain boundary conditions are specified through communications between processors which are organized by 263 explicit statements (message passing method). 264 The present implementation is largely inspired by Guyon's work [Guyon 1995]. 259 265 260 266 The parallelization strategy is defined by the physical characteristics of the ocean model. … … 272 278 each processor sends to its neighbouring processors the update values of the points corresponding to 273 279 the interior overlapping area to its neighbouring sub-domain (\ie\ the innermost of the two overlapping rows). 274 Communications are first done according to the east-west direction and next according to the north-south direction. There is no specific communications for the corners. The communication is done through the Message Passing Interface (MPI) and requires \key{mpp\_mpi}. Use also \key{mpi2} if MPI3 is not available on your computer. 280 Communications are first done according to the east-west direction and next according to the north-south direction. 281 There is no specific communications for the corners. 282 The communication is done through the Message Passing Interface (MPI) and requires \key{mpp\_mpi}. 283 Use also \key{mpi2} if MPI3 is not available on your computer. 275 284 The data exchanges between processors are required at the very place where 276 285 lateral domain boundary conditions are set in the mono-domain computation: … … 285 294 \includegraphics[width=\textwidth]{Fig_mpp} 286 295 \caption{ 287 \protect\label{fig: mpp}296 \protect\label{fig:LBC_mpp} 288 297 Positioning of a sub-domain when massively parallel processing is used. 289 298 } … … 292 301 %>>>>>>>>>>>>>>>>>>>>>>>>>>>> 293 302 294 In \NEMO, the splitting is regular and arithmetic. The total number of subdomains corresponds to the number of MPI processes allocated to \NEMO\ when the model is launched (\ie\ mpirun -np x ./nemo will automatically give x subdomains). The i-axis is divided by \np{jpni} and the j-axis by \np{jpnj}. These parameters are defined in \nam{mpp} namelist. If \np{jpni} and \np{jpnj} are < 1, they will be automatically redefined in the code to give the best domain decomposition (see bellow). 295 296 Each processor is independent and without message passing or synchronous process, programs run alone and access just its own local memory. For this reason, the main model dimensions are now the local dimensions of the subdomain (pencil) that are named \jp{jpi}, \jp{jpj}, \jp{jpk}. 297 These dimensions include the internal domain and the overlapping rows. The number of rows to exchange (known as the halo) is usually set to one (nn\_hls=1, in \mdl{par\_oce}, and must be kept to one until further notice). The whole domain dimensions are named \jp{jpiglo}, \jp{jpjglo} and \jp{jpk}. The relationship between the whole domain and a sub-domain is: 298 \[ 299 jpi = ( jpiglo-2\times nn\_hls + (jpni-1) ) / jpni + 2\times nn\_hls 300 \] 301 \[ 303 In \NEMO, the splitting is regular and arithmetic. 304 The total number of subdomains corresponds to the number of MPI processes allocated to \NEMO\ when the model is launched 305 (\ie\ mpirun -np x ./nemo will automatically give x subdomains). 306 The i-axis is divided by \np{jpni} and the j-axis by \np{jpnj}. 307 These parameters are defined in \nam{mpp} namelist. 308 If \np{jpni} and \np{jpnj} are < 1, they will be automatically redefined in the code to give the best domain decomposition 309 (see bellow). 310 311 Each processor is independent and without message passing or synchronous process, programs run alone and access just its own local memory. 312 For this reason, 313 the main model dimensions are now the local dimensions of the subdomain (pencil) that are named \jp{jpi}, \jp{jpj}, \jp{jpk}. 314 These dimensions include the internal domain and the overlapping rows. 315 The number of rows to exchange (known as the halo) is usually set to one (nn\_hls=1, in \mdl{par\_oce}, 316 and must be kept to one until further notice). 317 The whole domain dimensions are named \jp{jpiglo}, \jp{jpjglo} and \jp{jpk}. 318 The relationship between the whole domain and a sub-domain is: 319 \begin{gather*} 320 jpi = ( jpiglo-2\times nn\_hls + (jpni-1) ) / jpni + 2\times nn\_hls \\ 302 321 jpj = ( jpjglo-2\times nn\_hls + (jpnj-1) ) / jpnj + 2\times nn\_hls 303 \ ]304 305 One also defines variables nldi and nlei which correspond to the internal domain bounds, and the variables nimpp and njmpp which are the position of the (1,1) grid-point in the global domain (\autoref{fig: mpp}). Note that since the version 4, there is no more extra-halo area as defined in \autoref{fig:mpp} so \jp{jpi} is now always equal to nlci and \jp{jpj} equal to nlcj.322 \end{gather*} 323 324 One also defines variables nldi and nlei which correspond to the internal domain bounds, and the variables nimpp and njmpp which are the position of the (1,1) grid-point in the global domain (\autoref{fig:LBC_mpp}). Note that since the version 4, there is no more extra-halo area as defined in \autoref{fig:LBC_mpp} so \jp{jpi} is now always equal to nlci and \jp{jpj} equal to nlcj. 306 325 307 326 An element of $T_{l}$, a local array (subdomain) corresponds to an element of $T_{g}$, 308 327 a global array (whole domain) by the relationship: 309 328 \[ 310 % \label{eq: lbc_nimpp}329 % \label{eq:LBC_nimpp} 311 330 T_{g} (i+nimpp-1,j+njmpp-1,k) = T_{l} (i,j,k), 312 331 \] … … 322 341 323 342 If the domain decomposition is automatically defined (when \np{jpni} and \np{jpnj} are < 1), the decomposition chosen by the model will minimise the sub-domain size (defined as $max_{all domains}(jpi \times jpj)$) and maximize the number of eliminated land subdomains. This means that no other domain decomposition (a set of \np{jpni} and \np{jpnj} values) will use less processes than $(jpni \times jpnj - N_{land})$ and get a smaller subdomain size. 324 In order to specify $N_{mpi}$ properly (minimize $N_{useless}$), you must run the model once with \np{ln\_list} activated. In this case, the model will start the initialisation phase, print the list of optimum decompositions ($N_{mpi}$, \np{jpni} and \np{jpnj}) in \texttt{ocean.output} and directly abort. The maximum value of $N_{mpi}$ tested in this list is given by $max(N_{MPI\_tasks}, \np{jpni} \times \np{jpnj})$. For example, run the model on 40 nodes with ln\_list activated and $\np{jpni} = 10000$ and $\np{jpnj} = 1$, will print the list of optimum domains decomposition from 1 to about 10000. 325 326 Processors are numbered from 0 to $N_{mpi} - 1$. Subdomains containning some ocean points are numbered first from 0 to $jpni * jpnj - N_{land} -1$. The remaining $N_{useless}$ land subdomains are numbered next, which means that, for a given (\np{jpni}, \np{jpnj}), the numbers attributed to he ocean subdomains do not vary with $N_{useless}$. 343 In order to specify $N_{mpi}$ properly (minimize $N_{useless}$), you must run the model once with \np{ln\_list} activated. In this case, the model will start the initialisation phase, print the list of optimum decompositions ($N_{mpi}$, \np{jpni} and \np{jpnj}) in \texttt{ocean.output} and directly abort. The maximum value of $N_{mpi}$ tested in this list is given by $max(N_{MPI\_tasks}, \np{jpni} \times \np{jpnj})$. For example, run the model on 40 nodes with ln\_list activated and $\np{jpni} = 10000$ and $\np{jpnj} = 1$, will print the list of optimum domains decomposition from 1 to about 10000. 344 345 Processors are numbered from 0 to $N_{mpi} - 1$. Subdomains containning some ocean points are numbered first from 0 to $jpni * jpnj - N_{land} -1$. The remaining $N_{useless}$ land subdomains are numbered next, which means that, for a given (\np{jpni}, \np{jpnj}), the numbers attributed to he ocean subdomains do not vary with $N_{useless}$. 327 346 328 347 When land processors are eliminated, the value corresponding to these locations in the model output files is undefined. \np{ln\_mskland} must be activated in order avoid Not a Number values in output files. Note that it is better to not eliminate land processors when creating a meshmask file (\ie\ when setting a non-zero value to \np{nn\_msh}). … … 332 351 \begin{center} 333 352 \includegraphics[width=\textwidth]{Fig_mppini2} 334 \caption 335 \protect\label{fig: mppini2}353 \caption[Atlantic domain]{ 354 \protect\label{fig:LBC_mppini2} 336 355 Example of Atlantic domain defined for the CLIPPER projet. 337 356 Initial grid is composed of 773 x 1236 horizontal points. … … 374 393 %---------------------------------------------- 375 394 \subsection{Namelists} 376 \label{subsec: BDY_namelist}395 \label{subsec:LBC_bdy_namelist} 377 396 378 397 The BDY module is activated by setting \np{ln\_bdy}\forcode{=.true.} . … … 384 403 In the example above, there are two boundary sets, the first of which is defined via a file and 385 404 the second is defined in the namelist. 386 For more details of the definition of the boundary geometry see section \autoref{subsec: BDY_geometry}.405 For more details of the definition of the boundary geometry see section \autoref{subsec:LBC_bdy_geometry}. 387 406 388 407 For each boundary set a boundary condition has to be chosen for the barotropic solution … … 441 460 %---------------------------------------------- 442 461 \subsection{Flow relaxation scheme} 443 \label{subsec: BDY_FRS_scheme}462 \label{subsec:LBC_bdy_FRS_scheme} 444 463 445 464 The Flow Relaxation Scheme (FRS) \citep{davies_QJRMS76,engedahl_T95}, … … 448 467 Given a model prognostic variable $\Phi$ 449 468 \[ 450 % \label{eq: bdy_frs1}469 % \label{eq:LBC_bdy_frs1} 451 470 \Phi(d) = \alpha(d)\Phi_{e}(d) + (1-\alpha(d))\Phi_{m}(d)\;\;\;\;\; d=1,N 452 471 \] … … 457 476 the prognostic equation for $\Phi$ of the form: 458 477 \[ 459 % \label{eq: bdy_frs2}478 % \label{eq:LBC_bdy_frs2} 460 479 -\frac{1}{\tau}\left(\Phi - \Phi_{e}\right) 461 480 \] 462 481 where the relaxation time scale $\tau$ is given by a function of $\alpha$ and the model time step $\Delta t$: 463 482 \[ 464 % \label{eq: bdy_frs3}483 % \label{eq:LBC_bdy_frs3} 465 484 \tau = \frac{1-\alpha}{\alpha} \,\rdt 466 485 \] … … 472 491 The function $\alpha$ is specified as a $tanh$ function: 473 492 \[ 474 % \label{eq: bdy_frs4}493 % \label{eq:LBC_bdy_frs4} 475 494 \alpha(d) = 1 - \tanh\left(\frac{d-1}{2}\right), \quad d=1,N 476 495 \] … … 480 499 %---------------------------------------------- 481 500 \subsection{Flather radiation scheme} 482 \label{subsec: BDY_flather_scheme}501 \label{subsec:LBC_bdy_flather_scheme} 483 502 484 503 The \citet{flather_JPO94} scheme is a radiation condition on the normal, 485 504 depth-mean transport across the open boundary. 486 505 It takes the form 487 \begin{equation} \label{eq:bdy_fla1} 488 U = U_{e} + \frac{c}{h}\left(\eta - \eta_{e}\right), 506 \begin{equation} 507 \label{eq:LBC_bdy_fla1} 508 U = U_{e} + \frac{c}{h}\left(\eta - \eta_{e}\right), 489 509 \end{equation} 490 510 where $U$ is the depth-mean velocity normal to the boundary and $\eta$ is the sea surface height, … … 495 515 the external depth-mean normal velocity, 496 516 plus a correction term that allows gravity waves generated internally to exit the model boundary. 497 Note that the sea-surface height gradient in \autoref{eq: bdy_fla1} is a spatial gradient across the model boundary,517 Note that the sea-surface height gradient in \autoref{eq:LBC_bdy_fla1} is a spatial gradient across the model boundary, 498 518 so that $\eta_{e}$ is defined on the $T$ points with $nbr=1$ and $\eta$ is defined on the $T$ points with $nbr=2$. 499 519 $U$ and $U_{e}$ are defined on the $U$ or $V$ points with $nbr=1$, \ie\ between the two $T$ grid points. … … 501 521 %---------------------------------------------- 502 522 \subsection{Orlanski radiation scheme} 503 \label{subsec: BDY_orlanski_scheme}523 \label{subsec:LBC_bdy_orlanski_scheme} 504 524 505 525 The Orlanski scheme is based on the algorithm described by \citep{marchesiello.mcwilliams.ea_OM01}, hereafter MMS. … … 507 527 The adaptive Orlanski condition solves a wave plus relaxation equation at the boundary: 508 528 \begin{equation} 509 \frac{\partial\phi}{\partial t} + c_x \frac{\partial\phi}{\partial x} + c_y \frac{\partial\phi}{\partial y} = 510 -\frac{1}{\tau}(\phi - \phi^{ext})511 \label{eq:wave_continuous} 529 \label{eq:LBC_wave_continuous} 530 \frac{\partial\phi}{\partial t} + c_x \frac{\partial\phi}{\partial x} + c_y \frac{\partial\phi}{\partial y} = 531 -\frac{1}{\tau}(\phi - \phi^{ext}) 512 532 \end{equation} 513 533 … … 515 535 velocities are diagnosed from the model fields as: 516 536 517 \begin{equation} \label{eq:cx} 518 c_x = -\frac{\partial\phi}{\partial t}\frac{\partial\phi / \partial x}{(\partial\phi /\partial x)^2 + (\partial\phi /\partial y)^2} 537 \begin{equation} 538 \label{eq:LBC_cx} 539 c_x = -\frac{\partial\phi}{\partial t}\frac{\partial\phi / \partial x}{(\partial\phi /\partial x)^2 + (\partial\phi /\partial y)^2} 519 540 \end{equation} 520 541 \begin{equation} 521 \label{eq:cy}522 c_y = -\frac{\partial\phi}{\partial t}\frac{\partial\phi / \partial y}{(\partial\phi /\partial x)^2 + (\partial\phi /\partial y)^2}542 \label{eq:LBC_cy} 543 c_y = -\frac{\partial\phi}{\partial t}\frac{\partial\phi / \partial y}{(\partial\phi /\partial x)^2 + (\partial\phi /\partial y)^2} 523 544 \end{equation} 524 545 525 546 (As noted by MMS, this is a circular diagnosis of the phase speeds which only makes sense on a discrete grid). 526 Equation (\autoref{eq: wave_continuous}) is defined adaptively depending on the sign of the phase velocity normal to the boundary $c_x$.547 Equation (\autoref{eq:LBC_wave_continuous}) is defined adaptively depending on the sign of the phase velocity normal to the boundary $c_x$. 527 548 For $c_x$ outward, we have 528 549 … … 534 555 535 556 \begin{equation} 536 \tau = \tau_{in}\,\,\,;\,\,\, c_x = c_y = 0 537 \label{eq:tau_in} 557 \label{eq:LBC_tau_in} 558 \tau = \tau_{in}\,\,\,;\,\,\, c_x = c_y = 0 538 559 \end{equation} 539 560 540 561 Generally the relaxation time scale at inward propagation points (\np{rn\_time\_dmp}) is set much shorter than the time scale at outward propagation 541 562 points (\np{rn\_time\_dmp\_out}) so that the solution is constrained more strongly by the external data at inward propagation points. 542 See \autoref{subsec: BDY_relaxation} for detailed on the spatial shape of the scaling.\\563 See \autoref{subsec:LBC_bdy_relaxation} for detailed on the spatial shape of the scaling.\\ 543 564 The ``normal propagation of oblique radiation'' or NPO approximation (called \forcode{'orlanski_npo'}) involves assuming 544 that $c_y$ is zero in equation (\autoref{eq: wave_continuous}), but including545 this term in the denominator of equation (\autoref{eq: cx}). Both versions of the scheme are options in BDY. Equations546 (\autoref{eq: wave_continuous}) - (\autoref{eq:tau_in}) correspond to equations (13) - (15) and (2) - (3) in MMS.\\565 that $c_y$ is zero in equation (\autoref{eq:LBC_wave_continuous}), but including 566 this term in the denominator of equation (\autoref{eq:LBC_cx}). Both versions of the scheme are options in BDY. Equations 567 (\autoref{eq:LBC_wave_continuous}) - (\autoref{eq:LBC_tau_in}) correspond to equations (13) - (15) and (2) - (3) in MMS.\\ 547 568 548 569 %---------------------------------------------- 549 570 \subsection{Relaxation at the boundary} 550 \label{subsec: BDY_relaxation}571 \label{subsec:LBC_bdy_relaxation} 551 572 552 573 In addition to a specific boundary condition specified as \np{cn\_tra} and \np{cn\_dyn3d}, relaxation on baroclinic velocities and tracers variables are available. … … 564 585 %---------------------------------------------- 565 586 \subsection{Boundary geometry} 566 \label{subsec: BDY_geometry}587 \label{subsec:LBC_bdy_geometry} 567 588 568 589 Each open boundary set is defined as a list of points. … … 615 636 %---------------------------------------------- 616 637 \subsection{Input boundary data files} 617 \label{subsec: BDY_data}638 \label{subsec:LBC_bdy_data} 618 639 619 640 The data files contain the data arrays in the order in which the points are defined in the $nbi$ and $nbj$ arrays. … … 655 676 %---------------------------------------------- 656 677 \subsection{Volume correction} 657 \label{subsec: BDY_vol_corr}678 \label{subsec:LBC_bdy_vol_corr} 658 679 659 680 There is an option to force the total volume in the regional model to be constant. … … 672 693 %---------------------------------------------- 673 694 \subsection{Tidal harmonic forcing} 674 \label{subsec: BDY_tides}695 \label{subsec:LBC_bdy_tides} 675 696 676 697 %-----------------------------------------nambdy_tide-------------------------------------------- -
NEMO/trunk/doc/latex/NEMO/subfiles/chap_LDF.tex
r11537 r11543 13 13 \newpage 14 14 15 The lateral physics terms in the momentum and tracer equations have been described in \autoref{eq: PE_zdf} and15 The lateral physics terms in the momentum and tracer equations have been described in \autoref{eq:MB_zdf} and 16 16 their discrete formulation in \autoref{sec:TRA_ldf} and \autoref{sec:DYN_ldf}). 17 17 In this section we further discuss each lateral physics option. … … 25 25 Note that this chapter describes the standard implementation of iso-neutral tracer mixing. 26 26 Griffies's implementation, which is used if \np{ln\_traldf\_triad}\forcode{=.true.}, 27 is described in \autoref{apdx: triad}27 is described in \autoref{apdx:TRIADS} 28 28 29 29 %-----------------------------------namtra_ldf - namdyn_ldf-------------------------------------------- … … 82 82 the cell of the quantity to be diffused. 83 83 For a tracer, this leads to the following four slopes: 84 $r_{1u}$, $r_{1w}$, $r_{2v}$, $r_{2w}$ (see \autoref{eq: tra_ldf_iso}),84 $r_{1u}$, $r_{1w}$, $r_{2v}$, $r_{2w}$ (see \autoref{eq:TRA_ldf_iso}), 85 85 while for momentum the slopes are $r_{1t}$, $r_{1uw}$, $r_{2f}$, $r_{2uw}$ for $u$ and 86 86 $r_{1f}$, $r_{1vw}$, $r_{2t}$, $r_{2vw}$ for $v$. … … 92 92 In $s$-coordinates, geopotential mixing (\ie\ horizontal mixing) $r_1$ and $r_2$ are the slopes between 93 93 the geopotential and computational surfaces. 94 Their discrete formulation is found by locally solving \autoref{eq: tra_ldf_iso} when94 Their discrete formulation is found by locally solving \autoref{eq:TRA_ldf_iso} when 95 95 the diffusive fluxes in the three directions are set to zero and $T$ is assumed to be horizontally uniform, 96 96 \ie\ a linear function of $z_T$, the depth of a $T$-point. … … 98 98 99 99 \begin{equation} 100 \label{eq: ldfslp_geo}100 \label{eq:LDF_slp_geo} 101 101 \begin{aligned} 102 102 r_{1u} &= \frac{e_{3u}}{ \left( e_{1u}\;\overline{\overline{e_{3w}}}^{\,i+1/2,\,k} \right)} … … 125 125 Their discrete formulation is found using the fact that the diffusive fluxes of 126 126 locally referenced potential density (\ie\ $in situ$ density) vanish. 127 So, substituting $T$ by $\rho$ in \autoref{eq: tra_ldf_iso} and setting the diffusive fluxes in127 So, substituting $T$ by $\rho$ in \autoref{eq:TRA_ldf_iso} and setting the diffusive fluxes in 128 128 the three directions to zero leads to the following definition for the neutral slopes: 129 129 130 130 \begin{equation} 131 \label{eq: ldfslp_iso}131 \label{eq:LDF_slp_iso} 132 132 \begin{split} 133 133 r_{1u} &= \frac{e_{3u}}{e_{1u}}\; \frac{\delta_{i+1/2}[\rho]} … … 145 145 146 146 %gm% rewrite this as the explanation is not very clear !!! 147 %In practice, \autoref{eq: ldfslp_iso} is of little help in evaluating the neutral surface slopes. Indeed, for an unsimplified equation of state, the density has a strong dependancy on pressure (here approximated as the depth), therefore applying \autoref{eq:ldfslp_iso} using the $in situ$ density, $\rho$, computed at T-points leads to a flattening of slopes as the depth increases. This is due to the strong increase of the $in situ$ density with depth.148 149 %By definition, neutral surfaces are tangent to the local $in situ$ density \citep{mcdougall_JPO87}, therefore in \autoref{eq: ldfslp_iso}, all the derivatives have to be evaluated at the same local pressure (which in decibars is approximated by the depth in meters).150 151 %In the $z$-coordinate, the derivative of the \autoref{eq: ldfslp_iso} numerator is evaluated at the same depth \nocite{as what?} ($T$-level, which is the same as the $u$- and $v$-levels), so the $in situ$ density can be used for its evaluation.152 153 As the mixing is performed along neutral surfaces, the gradient of $\rho$ in \autoref{eq: ldfslp_iso} has to147 %In practice, \autoref{eq:LDF_slp_iso} is of little help in evaluating the neutral surface slopes. Indeed, for an unsimplified equation of state, the density has a strong dependancy on pressure (here approximated as the depth), therefore applying \autoref{eq:LDF_slp_iso} using the $in situ$ density, $\rho$, computed at T-points leads to a flattening of slopes as the depth increases. This is due to the strong increase of the $in situ$ density with depth. 148 149 %By definition, neutral surfaces are tangent to the local $in situ$ density \citep{mcdougall_JPO87}, therefore in \autoref{eq:LDF_slp_iso}, all the derivatives have to be evaluated at the same local pressure (which in decibars is approximated by the depth in meters). 150 151 %In the $z$-coordinate, the derivative of the \autoref{eq:LDF_slp_iso} numerator is evaluated at the same depth \nocite{as what?} ($T$-level, which is the same as the $u$- and $v$-levels), so the $in situ$ density can be used for its evaluation. 152 153 As the mixing is performed along neutral surfaces, the gradient of $\rho$ in \autoref{eq:LDF_slp_iso} has to 154 154 be evaluated at the same local pressure 155 155 (which, in decibars, is approximated by the depth in meters in the model). 156 Therefore \autoref{eq: ldfslp_iso} cannot be used as such,156 Therefore \autoref{eq:LDF_slp_iso} cannot be used as such, 157 157 but further transformation is needed depending on the vertical coordinate used: 158 158 … … 160 160 161 161 \item[$z$-coordinate with full step: ] 162 in \autoref{eq: ldfslp_iso} the densities appearing in the $i$ and $j$ derivatives are taken at the same depth,162 in \autoref{eq:LDF_slp_iso} the densities appearing in the $i$ and $j$ derivatives are taken at the same depth, 163 163 thus the $in situ$ density can be used. 164 164 This is not the case for the vertical derivatives: $\delta_{k+1/2}[\rho]$ is replaced by $-\rho N^2/g$, … … 173 173 in the current release of \NEMO, iso-neutral mixing is only employed for $s$-coordinates if 174 174 the Griffies scheme is used (\np{ln\_traldf\_triad}\forcode{=.true.}; 175 see \autoref{apdx: triad}).175 see \autoref{apdx:TRIADS}). 176 176 In other words, iso-neutral mixing will only be accurately represented with a linear equation of state 177 177 (\np{ln\_seos}\forcode{=.true.}). 178 In the case of a "true" equation of state, the evaluation of $i$ and $j$ derivatives in \autoref{eq: ldfslp_iso}178 In the case of a "true" equation of state, the evaluation of $i$ and $j$ derivatives in \autoref{eq:LDF_slp_iso} 179 179 will include a pressure dependent part, leading to the wrong evaluation of the neutral slopes. 180 180 … … 193 193 194 194 \[ 195 % \label{eq: ldfslp_iso2}195 % \label{eq:LDF_slp_iso2} 196 196 \begin{split} 197 197 r_{1u} &= \frac{e_{3u}}{e_{1u}}\; \frac … … 230 230 To overcome this problem, several techniques have been proposed in which the numerical schemes of 231 231 the ocean model are modified \citep{weaver.eby_JPO97, griffies.gnanadesikan.ea_JPO98}. 232 Griffies's scheme is now available in \NEMO\ if \np{ln\_traldf\_triad}\forcode{ =.true.}; see \autoref{apdx:triad}.232 Griffies's scheme is now available in \NEMO\ if \np{ln\_traldf\_triad}\forcode{ = .true.}; see \autoref{apdx:TRIADS}. 233 233 Here, another strategy is presented \citep{lazar_phd97}: 234 234 a local filtering of the iso-neutral slopes (made on 9 grid-points) prevents the development of … … 280 280 \includegraphics[width=\textwidth]{Fig_eiv_slp} 281 281 \caption{ 282 \protect\label{fig: eiv_slp}282 \protect\label{fig:LDF_eiv_slp} 283 283 Vertical profile of the slope used for lateral mixing in the mixed layer: 284 284 \textit{(a)} in the real ocean the slope is the iso-neutral slope in the ocean interior, … … 304 304 The iso-neutral diffusion operator on momentum is the same as the one used on tracers but 305 305 applied to each component of the velocity separately 306 (see \autoref{eq: dyn_ldf_iso} in section~\autoref{subsec:DYN_ldf_iso}).306 (see \autoref{eq:DYN_ldf_iso} in section~\autoref{subsec:DYN_ldf_iso}). 307 307 The slopes between the surface along which the diffusion operator acts and the surface of computation 308 308 ($z$- or $s$-surfaces) are defined at $T$-, $f$-, and \textit{uw}- points for the $u$-component, and $T$-, $f$- and 309 309 \textit{vw}- points for the $v$-component. 310 310 They are computed from the slopes used for tracer diffusion, 311 \ie\ \autoref{eq: ldfslp_geo} and \autoref{eq:ldfslp_iso}:311 \ie\ \autoref{eq:LDF_slp_geo} and \autoref{eq:LDF_slp_iso}: 312 312 313 313 \[ 314 % \label{eq: ldfslp_dyn}314 % \label{eq:LDF_slp_dyn} 315 315 \begin{aligned} 316 316 &r_{1t}\ \ = \overline{r_{1u}}^{\,i} &&& r_{1f}\ \ &= \overline{r_{1u}}^{\,i+1/2} \\ … … 371 371 372 372 \begin{equation} 373 \label{eq: constantah}373 \label{eq:LDF_constantah} 374 374 A_o^l = \left\{ 375 375 \begin{aligned} … … 386 386 387 387 In the vertically varying case, a hyperbolic variation of the lateral mixing coefficient is introduced in which 388 the surface value is given by \autoref{eq: constantah}, the bottom value is 1/4 of the surface value,388 the surface value is given by \autoref{eq:LDF_constantah}, the bottom value is 1/4 of the surface value, 389 389 and the transition takes place around z=500~m with a width of 200~m. 390 390 This profile is hard coded in module \mdl{ldfc1d\_c2d}, but can be easily modified by users. … … 396 396 the type of operator used: 397 397 \begin{equation} 398 \label{eq: title}398 \label{eq:LDF_title} 399 399 A_l = \left\{ 400 400 \begin{aligned} … … 411 411 model configurations presenting large changes in grid spacing such as global ocean models. 412 412 Indeed, in such a case, a constant mixing coefficient can lead to a blow up of the model due to 413 large coefficient compare to the smallest grid size (see \autoref{sec: STP_forward_imp}),413 large coefficient compare to the smallest grid size (see \autoref{sec:TD_forward_imp}), 414 414 especially when using a bilaplacian operator. 415 415 … … 429 429 430 430 \begin{equation} 431 \label{eq: flowah}431 \label{eq:LDF_flowah} 432 432 A_l = \left\{ 433 433 \begin{aligned} … … 445 445 446 446 \begin{equation} 447 \label{eq: smag1}447 \label{eq:LDF_smag1} 448 448 \begin{split} 449 449 T_{smag}^{-1} & = \sqrt{\left( \partial_x u - \partial_y v\right)^2 + \left( \partial_y u + \partial_x v\right)^2 } \\ … … 455 455 456 456 \begin{equation} 457 \label{eq: smag2}457 \label{eq:LDF_smag2} 458 458 A_{smag} = \left\{ 459 459 \begin{aligned} … … 464 464 \end{equation} 465 465 466 For stability reasons, upper and lower limits are applied on the resulting coefficient (see \autoref{sec: STP_forward_imp}) so that:467 \begin{equation} 468 \label{eq: smag3}466 For stability reasons, upper and lower limits are applied on the resulting coefficient (see \autoref{sec:TD_forward_imp}) so that: 467 \begin{equation} 468 \label{eq:LDF_smag3} 469 469 \begin{aligned} 470 470 & C_{min} \frac{1}{2} \lvert U \rvert e < A_{smag} < C_{max} \frac{e^2}{ 8\rdt} & \text{for laplacian operator } \\ … … 480 480 481 481 (1) the momentum diffusion operator acting along model level surfaces is written in terms of curl and 482 divergent components of the horizontal current (see \autoref{subsec: PE_ldf}).482 divergent components of the horizontal current (see \autoref{subsec:MB_ldf}). 483 483 Although the eddy coefficient could be set to different values in these two terms, 484 484 this option is not currently available. … … 486 486 (2) with an horizontally varying viscosity, the quadratic integral constraints on enstrophy and on the square of 487 487 the horizontal divergence for operators acting along model-surfaces are no longer satisfied 488 (\autoref{sec: dynldf_properties}).488 (\autoref{sec:INVARIANTS_dynldf_properties}). 489 489 490 490 % ================================================================ … … 527 527 the formulation of which depends on the slopes of iso-neutral surfaces. 528 528 Contrary to the case of iso-neutral mixing, the slopes used here are referenced to the geopotential surfaces, 529 \ie\ \autoref{eq: ldfslp_geo} is used in $z$-coordinates,530 and the sum \autoref{eq: ldfslp_geo} + \autoref{eq:ldfslp_iso} in $s$-coordinates.529 \ie\ \autoref{eq:LDF_slp_geo} is used in $z$-coordinates, 530 and the sum \autoref{eq:LDF_slp_geo} + \autoref{eq:LDF_slp_iso} in $s$-coordinates. 531 531 532 532 If isopycnal mixing is used in the standard way, \ie\ \np{ln\_traldf\_triad}\forcode{=.false.}, the eddy induced velocity is given by: 533 533 \begin{equation} 534 \label{eq: ldfeiv}534 \label{eq:LDF_eiv} 535 535 \begin{split} 536 536 u^* & = \frac{1}{e_{2u}e_{3u}}\; \delta_k \left[e_{2u} \, A_{uw}^{eiv} \; \overline{r_{1w}}^{\,i+1/2} \right]\\ … … 554 554 \colorbox{yellow}{CASE \np{nn\_aei\_ijk\_t} = 21 to be added} 555 555 556 In case of setting \np{ln\_traldf\_triad}\forcode{ =.true.}, a skew form of the eddy induced advective fluxes is used, which is described in \autoref{apdx:triad}.556 In case of setting \np{ln\_traldf\_triad}\forcode{ = .true.}, a skew form of the eddy induced advective fluxes is used, which is described in \autoref{apdx:TRIADS}. 557 557 558 558 % ================================================================ -
NEMO/trunk/doc/latex/NEMO/subfiles/chap_OBS.tex
r11435 r11543 691 691 692 692 Examples of the weights calculated for an observation with rectangular and radial footprints are shown in 693 \autoref{fig: obsavgrec} and~\autoref{fig:obsavgrad}.693 \autoref{fig:OBS_avgrec} and~\autoref{fig:OBS_avgrad}. 694 694 695 695 %>>>>>>>>>>>>>>>>>>>>>>>>>>>> … … 698 698 \includegraphics[width=\textwidth]{Fig_OBS_avg_rec} 699 699 \caption{ 700 \protect\label{fig: obsavgrec}700 \protect\label{fig:OBS_avgrec} 701 701 Weights associated with each model grid box (blue lines and numbers) 702 702 for an observation at -170.5\deg{E}, 56.0\deg{N} with a rectangular footprint of 1\deg x 1\deg. … … 711 711 \includegraphics[width=\textwidth]{Fig_OBS_avg_rad} 712 712 \caption{ 713 \protect\label{fig: obsavgrad}713 \protect\label{fig:OBS_avgrad} 714 714 Weights associated with each model grid box (blue lines and numbers) 715 715 for an observation at -170.5\deg{E}, 56.0\deg{N} with a radial footprint with diameter 1\deg. … … 756 756 ({\phi_{}}_{\mathrm D} \; - \; {\phi_{}}_{\mathrm P} )] \; \widehat{\mathbf k} \\ 757 757 \end{array} 758 % \label{eq: cross}758 % \label{eq:OBS_cross} 759 759 \end{align*} 760 760 point in the opposite direction to the unit normal $\widehat{\mathbf k}$ … … 791 791 \includegraphics[width=\textwidth]{Fig_ASM_obsdist_local} 792 792 \caption{ 793 \protect\label{fig: obslocal}793 \protect\label{fig:OBS_local} 794 794 Example of the distribution of observations with the geographical distribution of observational data. 795 795 } … … 800 800 This is the simplest option in which the observations are distributed according to 801 801 the domain of the grid-point parallelization. 802 \autoref{fig: obslocal} shows an example of the distribution of the {\em in situ} data on processors with802 \autoref{fig:OBS_local} shows an example of the distribution of the {\em in situ} data on processors with 803 803 a different colour for each observation on a given processor for a 4 $\times$ 2 decomposition with ORCA2. 804 804 The grid-point domain decomposition is clearly visible on the plot. … … 820 820 \includegraphics[width=\textwidth]{Fig_ASM_obsdist_global} 821 821 \caption{ 822 \protect\label{fig: obsglobal}822 \protect\label{fig:OBS_global} 823 823 Example of the distribution of observations with the round-robin distribution of observational data. 824 824 } … … 830 830 use message passing in order to retrieve the stencil for interpolation. 831 831 The simplest distribution of the observations is to distribute them using a round-robin scheme. 832 \autoref{fig: obsglobal} shows the distribution of the {\em in situ} data on processors for832 \autoref{fig:OBS_global} shows the distribution of the {\em in situ} data on processors for 833 833 the round-robin distribution of observations with a different colour for each observation on a given processor for 834 a 4 $\times$ 2 decomposition with ORCA2 for the same input data as in \autoref{fig: obslocal}.834 a 4 $\times$ 2 decomposition with ORCA2 for the same input data as in \autoref{fig:OBS_local}. 835 835 The observations are now clearly randomly distributed on the globe. 836 836 In order to be able to perform horizontal interpolation in this case, … … 1118 1118 \end{minted} 1119 1119 1120 \autoref{fig: obsdataplotmain} shows the main window which is launched when dataplot starts.1120 \autoref{fig:OBS_dataplotmain} shows the main window which is launched when dataplot starts. 1121 1121 This is split into three parts. 1122 1122 At the top there is a menu bar which contains a variety of drop down menus. … … 1154 1154 \includegraphics[width=\textwidth]{Fig_OBS_dataplot_main} 1155 1155 \caption{ 1156 \protect\label{fig: obsdataplotmain}1156 \protect\label{fig:OBS_dataplotmain} 1157 1157 Main window of dataplot. 1158 1158 } … … 1162 1162 1163 1163 If a profile point is clicked with the mouse button a plot of the observation and background values as 1164 a function of depth (\autoref{fig: obsdataplotprofile}).1164 a function of depth (\autoref{fig:OBS_dataplotprofile}). 1165 1165 1166 1166 %>>>>>>>>>>>>>>>>>>>>>>>>>>>> … … 1170 1170 \includegraphics[width=\textwidth]{Fig_OBS_dataplot_prof} 1171 1171 \caption{ 1172 \protect\label{fig: obsdataplotprofile}1172 \protect\label{fig:OBS_dataplotprofile} 1173 1173 Profile plot from dataplot produced by right clicking on a point in the main window. 1174 1174 } -
NEMO/trunk/doc/latex/NEMO/subfiles/chap_SBC.tex
r11537 r11543 109 109 Next, the scheme for interpolation on the fly is described. 110 110 Finally, the different options that further modify the fluxes applied to the ocean are discussed. 111 One of these is modification by icebergs (see \autoref{sec: ICB_icebergs}),111 One of these is modification by icebergs (see \autoref{sec:SBC_ICB_icebergs}), 112 112 which act as drifting sources of fresh water. 113 113 Another example of modification is that due to the ice shelf melting/freezing (see \autoref{sec:SBC_isf}), … … 124 124 The surface ocean stress is the stress exerted by the wind and the sea-ice on the ocean. 125 125 It is applied in \mdl{dynzdf} module as a surface boundary condition of the computation of 126 the momentum vertical mixing trend (see \autoref{eq: dynzdf_sbc} in \autoref{sec:DYN_zdf}).126 the momentum vertical mixing trend (see \autoref{eq:DYN_zdf_sbc} in \autoref{sec:DYN_zdf}). 127 127 As such, it has to be provided as a 2D vector interpolated onto the horizontal velocity ocean mesh, 128 128 \ie\ resolved onto the model (\textbf{i},\textbf{j}) direction at $u$- and $v$-points. … … 135 135 It is applied in \mdl{trasbc} module as a surface boundary condition trend of 136 136 the first level temperature time evolution equation 137 (see \autoref{eq: tra_sbc} and \autoref{eq:tra_sbc_lin} in \autoref{subsec:TRA_sbc}).