Changeset 4 for vendor/nemo/current/DOC/TexFiles
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vendor/nemo/current/DOC/TexFiles/Chapters/Annex_ISO.tex
r1 r4 2 2 % Iso-neutral diffusion : 3 3 % ================================================================ 4 \chapter{Griffies's iso-neutral diffusion} 4 \chapter[Iso-neutral diffusion and eddy advection using 5 triads]{Iso-neutral diffusion and eddy advection using triads} 5 6 \label{sec:triad} 6 7 \minitoc 7 8 \section{Griffies's formulation of iso-neutral diffusion} 8 \pagebreak 9 \section{Choice of namelist parameters} 10 %-----------------------------------------nam_traldf------------------------------------------------------ 11 \namdisplay{namtra_ldf} 12 %--------------------------------------------------------------------------------------------------------- 13 If the namelist variable \np{ln\_traldf\_grif} is set true (and 14 \key{ldfslp} is set), \NEMO updates both active and passive tracers 15 using the Griffies triad representation of iso-neutral diffusion and 16 the eddy-induced advective skew (GM) fluxes. Otherwise (by default) the 17 filtered version of Cox's original scheme is employed 18 (\S\ref{LDF_slp}). In the present implementation of the Griffies 19 scheme, the advective skew fluxes are implemented even if 20 \key{traldf\_eiv} is not set. 21 22 Values of iso-neutral diffusivity and GM coefficient are set as 23 described in \S\ref{LDF_coef}. If none of the keys \key{traldf\_cNd}, 24 N=1,2,3 is set (the default), spatially constant iso-neutral $A_l$ and 25 GM diffusivity $A_e$ are directly set by \np{rn\_aeih\_0} and 26 \np{rn\_aeiv\_0}. If 2D-varying coefficients are set with 27 \key{traldf\_c2d} then $A_l$ is reduced in proportion with horizontal 28 scale factor according to \eqref{Eq_title} \footnote{Except in global 29 $0.5^{\circ}$ runs (\key{orca\_r05}) with \key{traldf\_eiv}, where 30 $A_l$ is set like $A_e$ but with a minimum vale of 31 $100\;\mathrm{m}^2\;\mathrm{s}^{-1}$}. In idealised setups with 32 \key{traldf\_c2d}, $A_e$ is reduced similarly, but if \key{traldf\_eiv} 33 is set in the global configurations \key{orca\_r2}, \key{orca\_r1} or 34 \key{orca\_r05} with \key{traldf\_c2d}, a horizontally varying $A_e$ is 35 instead set from the Held-Larichev parameterisation\footnote{In this 36 case, $A_e$ at low latitudes $|\theta|<20^{\circ}$ is further 37 reduced by a factor $|f/f_{20}|$, where $f_{20}$ is the value of $f$ 38 at $20^{\circ}$~N} (\mdl{ldfeiv}) and \np{rn\_aeiv\_0} is ignored 39 unless it is zero. 40 41 The options specific to the Griffies scheme include: 42 \begin{description}[font=\normalfont] 43 \item[\np{ln\_traldf\_gdia}] Default value is false. See \S\ref{sec:triad:sfdiag}. If this is set true, time-mean 44 eddy-advective (GM) velocities are output for diagnostic purposes, even 45 though the eddy advection is accomplished by means of the skew 46 fluxes. 47 \item[\np{ln\_traldf\_iso}] See \S\ref{sec:triad:taper}. If this is set false (the default), then 48 `iso-neutral' mixing is accomplished within the surface mixed-layer 49 along slopes linearly decreasing with depth from the value immediately below 50 the mixed-layer to zero (flat) at the surface (\S\ref{sec:triad:lintaper}). This is the same 51 treatment as used in the default implementation 52 \S\ref{LDF_slp_iso}; Fig.~\ref{Fig_eiv_slp}. Where 53 \np{ln\_traldf\_iso} is set true, the vertical skew flux is further 54 reduced to ensure no vertical buoyancy flux, giving an almost pure 55 horizontal diffusive tracer flux within the mixed layer. This is similar to 56 the tapering suggested by \citet{Gerdes1991}. See \S\ref{sec:triad:Gerdes-taper} 57 \item[\np{ln\_traldf\_botmix}] See \S\ref{sec:triad:iso_bdry}. If this 58 is set false (the default) then the lateral diffusive fluxes 59 associated with triads partly masked by topography are neglected. If 60 it is set true, however, then these lateral diffusive fluxes are 61 applied, giving smoother bottom tracer fields at the cost of 62 introducing diapycnal mixing. 63 \end{description} 64 \section{Triad formulation of iso-neutral diffusion} 9 65 \label{sec:triad:iso} 10 11 We define a scheme inspired by \citet{Griffies_al_JPO98}, but formulated within the \NEMO 66 We have implemented into \NEMO a scheme inspired by \citet{Griffies_al_JPO98}, but formulated within the \NEMO 12 67 framework, using scale factors rather than grid-sizes. 13 68 … … 147 202 % >>>>>>>>>>>>>>>>>>>>>>>>>>>> 148 203 \begin{figure}[h] \begin{center} 149 \includegraphics[width= 0.90\textwidth]{./TexFiles/Figures/Fig_triad_fluxes}204 \includegraphics[width=1.05\textwidth]{./TexFiles/Figures/Fig_GRIFF_triad_fluxes} 150 205 \caption{ \label{fig:triad:ISO_triad} 151 206 (a) Arrangement of triads $S_i$ and tracer gradients to … … 215 270 % >>>>>>>>>>>>>>>>>>>>>>>>>>>> 216 271 \begin{figure}[h] \begin{center} 217 \includegraphics[width=0. 60\textwidth]{./TexFiles/Figures/Fig_qcells}272 \includegraphics[width=0.80\textwidth]{./TexFiles/Figures/Fig_GRIFF_qcells} 218 273 \caption{ \label{fig:triad:qcells} 219 Triad notation for quarter cells. $T$-cells are inside274 Triad notation for quarter cells. $T$-cells are inside 220 275 boxes, while the $i+\half,k$ $u$-cell is shaded in green and the 221 276 $i,k+\half$ $w$-cell is shaded in pink.} … … 613 668 or $i+1,k+1$ tracer points is masked, i.e.\ the $i,k+1$ $u$-point is 614 669 masked. The associated lateral fluxes (grey-black dashed line) are 615 masked if \n lv{ln\_botmix\_grif=.false.}, but left unmasked,616 giving bottom mixing, if \n lv{ln\_botmix\_grif=.true.}.617 618 The default option \n lv{ln\_botmix\_grif=.false.}is suitable when the619 bbl mixing option is enabled (\key{trabbl}, with \n lv{nn\_bbl\_ldf=1}),670 masked if \np{ln\_botmix\_grif}=false, but left unmasked, 671 giving bottom mixing, if \np{ln\_botmix\_grif}=true. 672 673 The default option \np{ln\_botmix\_grif}=false is suitable when the 674 bbl mixing option is enabled (\key{trabbl}, with \np{nn\_bbl\_ldf}=1), 620 675 or for simple idealized problems. For setups with topography without 621 bbl mixing, \n lv{ln\_botmix\_grif=.true.}may be necessary.676 bbl mixing, \np{ln\_botmix\_grif}=true may be necessary. 622 677 % >>>>>>>>>>>>>>>>>>>>>>>>>>>> 623 678 \begin{figure}[h] \begin{center} 624 \includegraphics[width=0.60\textwidth]{./TexFiles/Figures/Fig_ bdry_triads}679 \includegraphics[width=0.60\textwidth]{./TexFiles/Figures/Fig_GRIFF_bdry_triads} 625 680 \caption{ \label{fig:triad:bdry_triads} 626 681 (a) Uppermost model layer $k=1$ with $i,1$ and $i+1,1$ tracer … … 636 691 or $i+1,k+1$ tracer points is masked, i.e.\ the $i,k+1$ $u$-point 637 692 is masked. The associated lateral fluxes (grey-black dashed 638 line) are masked if \ smnlv{ln\_botmix\_grif=.false.}, but left639 unmasked, giving bottom mixing, if \ smnlv{ln\_botmix\_grif=.true.}}693 line) are masked if \np{botmix\_grif}=.false., but left 694 unmasked, giving bottom mixing, if \np{botmix\_grif}=.true.} 640 695 \end{center} \end{figure} 641 696 % >>>>>>>>>>>>>>>>>>>>>>>>>>>> … … 665 720 iso-neutral density flux that drives dianeutral mixing. In particular this iso-neutral density flux 666 721 is always downwards, and so acts to reduce gravitational potential energy. 667 \subsection{Tapering within the surface mixed layer} 722 \subsection{Tapering within the surface mixed layer}\label{sec:triad:taper} 723 668 724 Additional tapering of the iso-neutral fluxes is necessary within the 669 725 surface mixed layer. When the Griffies triads are used, we offer two … … 671 727 \subsubsection{Linear slope tapering within the surface mixed layer}\label{sec:triad:lintaper} 672 728 This is the option activated by the default choice 673 \n lv{ln\_triad\_iso=.false.}. Slopes $\tilde{r}_i$ relative to729 \np{ln\_triad\_iso}=false. Slopes $\tilde{r}_i$ relative to 674 730 geopotentials are tapered linearly from their value immediately below the mixed layer to zero at the 675 731 surface, as described in option (c) of Fig.~\ref{Fig_eiv_slp}, to values … … 794 850 different $i_p,k_p$, denoted by different colours, (e.g. the green 795 851 triad $i_p=1/2,k_p=-1/2$) are tapered to the appropriate basal triad.}} 796 {\includegraphics[width=0.60\textwidth]{./TexFiles/Figures/Fig_ triad_MLB}}852 {\includegraphics[width=0.60\textwidth]{./TexFiles/Figures/Fig_GRIFF_MLB_triads}} 797 853 \end{figure} 798 854 % >>>>>>>>>>>>>>>>>>>>>>>>>>>> 799 855 800 \subsubsection{Additional truncation of skew iso-neutral flux components} 801 The alternative option is activated by setting \nlv{ln\_triad\_iso = 802 .true.}. This retains the same tapered slope $\rML$ described above for the 856 \subsubsection{Additional truncation of skew iso-neutral flux 857 components} 858 \label{sec:triad:Gerdes-taper} 859 The alternative option is activated by setting \np{ln\_triad\_iso} = 860 true. This retains the same tapered slope $\rML$ described above for the 803 861 calculation of the $_{33}$ term of the iso-neutral diffusion tensor (the 804 862 vertical tracer flux driven by vertical tracer gradients), but … … 839 897 % Skew flux formulation for Eddy Induced Velocity : 840 898 % ================================================================ 841 \section{Eddy induced advection and its formulation as a skewflux}899 \section{Eddy induced advection formulated as a skew flux}\label{sec:triad:skew-flux} 842 900 843 901 \subsection{The continuous skew flux formulation}\label{sec:triad:continuous-skew-flux} 844 902 845 When Gent and McWilliams's [1990] diffusion is used (\key{traldf\_eiv} defined),903 When Gent and McWilliams's [1990] diffusion is used, 846 904 an additional advection term is added. The associated velocity is the so called 847 905 eddy induced velocity, the formulation of which depends on the slopes of iso- … … 852 910 853 911 The eddy induced velocity is given by: 854 \begin{equation} \label{eq:triad:eiv_v} 912 \begin{subequations} \label{eq:triad:eiv} 913 \begin{equation}\label{eq:triad:eiv_v} 855 914 \begin{split} 856 u^* & = - \frac{1}{e_{3}}\; \partial_ k \left( A_{e} \; \tilde{r}_1 \right)\\857 v^* & = - \frac{1}{e_{3}}\; \partial_ k \left( A_{e} \; \tilde{r}_2 \right)\\858 w^* & = \frac{1}{e_{1}e_{2}}\; \left\{ \partial_i \left( e_{2} \, A_{e} \; \tilde{r}_1\right)859 + \partial_j \left( e_{1} \, A_{e} \;\tilde{r}_2 \right) \right\}915 u^* & = - \frac{1}{e_{3}}\; \partial_i\psi_1, \\ 916 v^* & = - \frac{1}{e_{3}}\; \partial_j\psi_2, \\ 917 w^* & = \frac{1}{e_{1}e_{2}}\; \left\{ \partial_i \left( e_{2} \, \psi_1\right) 918 + \partial_j \left( e_{1} \, \psi_2\right) \right\}, 860 919 \end{split} 861 920 \end{equation} 862 where $A_{e}$ is the eddy induced velocity coefficient, and $\tilde{r}_1$ and $\tilde{r}_2$ the slopes between the iso-neutral and the geopotential surfaces. 863 864 The traditional way to implement this additional advection is to add it to the Eulerian 865 velocity prior to computing the tracer advection. This allows us to take advantage of 866 all the advection schemes offered for the tracers (see \S\ref{TRA_adv}) and not just 867 a $2^{nd}$ order advection scheme. This is particularly useful for passive tracers 868 where \emph{positivity} of the advection scheme is of paramount importance. 869 870 \citet{Griffies_JPO98} introduces another way to implement the eddy induced advection, 871 the so-called skew form. It is based on a transformation of the advective fluxes 921 where the streamfunctions $\psi_i$ are given by 922 \begin{equation} \label{eq:triad:eiv_psi} 923 \begin{split} 924 \psi_1 & = A_{e} \; \tilde{r}_1, \\ 925 \psi_2 & = A_{e} \; \tilde{r}_2, 926 \end{split} 927 \end{equation} 928 \end{subequations} 929 with $A_{e}$ the eddy induced velocity coefficient, and $\tilde{r}_1$ and $\tilde{r}_2$ the slopes between the iso-neutral and the geopotential surfaces. 930 931 The traditional way to implement this additional advection is to add 932 it to the Eulerian velocity prior to computing the tracer 933 advection. This is implemented if \key{traldf\_eiv} is set in the 934 default implementation, where \np{ln\_traldf\_grif} is set 935 false. This allows us to take advantage of all the advection schemes 936 offered for the tracers (see \S\ref{TRA_adv}) and not just a $2^{nd}$ 937 order advection scheme. This is particularly useful for passive 938 tracers where \emph{positivity} of the advection scheme is of 939 paramount importance. 940 941 However, when \np{ln\_traldf\_grif} is set true, \NEMO instead 942 implements eddy induced advection according to the so-called skew form 943 \citep{Griffies_JPO98}. It is based on a transformation of the advective fluxes 872 944 using the non-divergent nature of the eddy induced velocity. 873 945 For example in the (\textbf{i},\textbf{k}) plane, the tracer advective … … 883 955 &= 884 956 \begin{pmatrix} 885 { - \partial_k \left( e_{2} \, A_{e} \; \tilde{r}_1 \right) \; T \;} \\886 {+ \partial_i \left( e_{2} \, A_{e} \; \tilde{r}_1 \right) \; T \;} \\957 { - \partial_k \left( e_{2} \,\psi_1 \right) \; T \;} \\ 958 {+ \partial_i \left( e_{2} \, \psi_1 \right) \; T \;} \\ 887 959 \end{pmatrix} \\ 888 960 &= 889 961 \begin{pmatrix} 890 { - \partial_k \left( e_{2} \, A_{e} \; \tilde{r}_1 \; T \right) \;} \\891 {+ \partial_i \left( e_{2} \, A_{e} \; \tilde{r}_1\; T \right) \;} \\962 { - \partial_k \left( e_{2} \, \psi_1 \; T \right) \;} \\ 963 {+ \partial_i \left( e_{2} \,\psi_1 \; T \right) \;} \\ 892 964 \end{pmatrix} 893 965 + 894 966 \begin{pmatrix} 895 {+ e_{2} \, A_{e} \; \tilde{r}_1 \; \partial_k T} \\896 { - e_{2} \, A_{e} \; \tilde{r}_1 \; \partial_i T} \\967 {+ e_{2} \, \psi_1 \; \partial_k T} \\ 968 { - e_{2} \, \psi_1 \; \partial_i T} \\ 897 969 \end{pmatrix} 898 970 \end{split} … … 902 974 \begin{equation} \label{eq:triad:eiv_skew_ijk} 903 975 \textbf{F}_\mathrm{eiv}^T = \begin{pmatrix} 904 {+ e_{2} \, A_{e} \; \tilde{r}_1 \; \partial_k T} \\905 { - e_{2} \, A_{e} \; \tilde{r}_1 \; \partial_i T} \\976 {+ e_{2} \, \psi_1 \; \partial_k T} \\ 977 { - e_{2} \, \psi_1 \; \partial_i T} \\ 906 978 \end{pmatrix} 907 979 \end{equation} … … 909 981 \begin{equation}\label{eq:triad:eiv_skew_physical} 910 982 \begin{split} 911 f^*_1 & = \frac{1}{e_{3}}\; A_{e} \; \tilde{r}_1 \partial_k T \\912 f^*_2 & = \frac{1}{e_{3}}\; A_{e} \; \tilde{r}_2 \partial_k T \\913 f^*_3 & = -\frac{1}{e_{1}e_{2}}\; A_{e} \left\{ e_{2} \tilde{r}_1 \partial_i T914 + e_{1} \ tilde{r}_2 \partial_j T \right\}. \\983 f^*_1 & = \frac{1}{e_{3}}\; \psi_1 \partial_k T \\ 984 f^*_2 & = \frac{1}{e_{3}}\; \psi_2 \partial_k T \\ 985 f^*_3 & = -\frac{1}{e_{1}e_{2}}\; \left\{ e_{2} \psi_1 \partial_i T 986 + e_{1} \psi_2 \partial_j T \right\}. \\ 915 987 \end{split} 916 988 \end{equation} 917 989 Note that Eq.~ \eqref{eq:triad:eiv_skew_physical} takes the same form whatever the 918 990 vertical coordinate, though of course the slopes 919 $\tilde{r}_i$ are relative to geopotentials.991 $\tilde{r}_i$ which define the $\psi_i$ in \eqref{eq:triad:eiv_psi} are relative to geopotentials. 920 992 The tendency associated with eddy induced velocity is then simply the convergence 921 993 of the fluxes (\ref{eq:triad:eiv_skew_ijk}, \ref{eq:triad:eiv_skew_physical}), so 922 994 \begin{equation} \label{eq:triad:skew_eiv_conv} 923 995 \frac{\partial T}{\partial t}= -\frac{1}{e_1 \, e_2 \, e_3 } \left[ 924 \frac{\partial}{\partial i} \left( e_2 A_{e} \; \tilde{r}_1 \partial_k T\right)925 + \frac{\partial}{\partial j} \left( e_1 A_{e}\;926 \ tilde{r}_2 \partial_k T\right)927 - \frac{\partial}{\partial k} A_{e} \left( e_{2} \tilde{r}_1 \partial_i T928 + e_{1} \ tilde{r}_2 \partial_j T \right) \right]996 \frac{\partial}{\partial i} \left( e_2 \psi_1 \partial_k T\right) 997 + \frac{\partial}{\partial j} \left( e_1 \; 998 \psi_2 \partial_k T\right) 999 - \frac{\partial}{\partial k} \left( e_{2} \psi_1 \partial_i T 1000 + e_{1} \psi_2 \partial_j T \right) \right] 929 1001 \end{equation} 930 1002 It naturally conserves the tracer content, as it is expressed in flux … … 976 1048 The discretization conserves tracer variance, $i.e.$ it does not 977 1049 include a diffusive component but is a `pure' advection term. This can 978 be seen either from Appendix \ref{Apdx_eiv_skew} or by considering the 1050 be seen 1051 %either from Appendix \ref{Apdx_eiv_skew} or 1052 by considering the 979 1053 fluxes associated with a given triad slope 980 1054 $_i^k{\mathbb{R}}_{i_p}^{k_p} (T)$. For, following … … 1064 1138 and $\triadt{i+1}{k}{R}{-1/2}{1/2}$ are masked when either of the 1065 1139 $i,k+1$ or $i+1,k+1$ tracer points is masked, i.e.\ the $i,k+1$ 1066 $u$-point is masked. The namelist parameter \n lv{ln\_botmix\_grif} has1140 $u$-point is masked. The namelist parameter \np{ln\_botmix\_grif} has 1067 1141 no effect on the eddy-induced skew-fluxes. 1068 1142 … … 1079 1153 option (c) of Fig.~\ref{Fig_eiv_slp}. This linear tapering for the 1080 1154 slopes used to calculate the eddy-induced fluxes is 1081 unaffected by the value of \n lv{ln\_triad\_iso}.1155 unaffected by the value of \np{ln\_triad\_iso}. 1082 1156 1083 1157 The justification for this linear slope tapering is that, for $A_e$ … … 1094 1168 1095 1169 \subsection{Streamfunction diagnostics}\label{sec:triad:sfdiag} 1096 Where the namelist parameter \n lv{ln\_botmix\_grif=.true.}, diagnosed1170 Where the namelist parameter \np{ln\_traldf\_gdia}=true, diagnosed 1097 1171 mean eddy-induced velocities are output. Each time step, 1098 1172 streamfunctions are calculated in the $i$-$k$ and $j$-$k$ planes at … … 1104 1178 \begin{equation} 1105 1179 \label{eq:triad:sfdiagi} 1106 {\psi_{[i]}}_{i+1/2}^{k+1/2}={\quarter}\sum_{\substack{i_p,\,k_p}} 1107 {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} 1108 \end{equation} 1109 1110 \newpage %force an empty line 1111 % ================================================================ 1112 % Discrete Invariants of the skew flux formulation 1113 % ================================================================ 1114 \subsection{Discrete Invariants of the skew flux formulation} 1115 \label{Apdx_eiv_skew} 1116 1117 1118 Demonstration for the conservation of the tracer variance in the (\textbf{i},\textbf{j}) plane. 1119 1120 This have to be moved in an Appendix. 1121 1122 The continuous property to be demonstrated is : 1123 \begin{align*} 1124 \int_D \nabla \cdot \textbf{F}_\mathrm{eiv}(T) \; T \;dv \equiv 0 1125 \end{align*} 1126 The discrete form of its left hand side is obtained using \eqref{eq:triad:allskewflux} 1127 \begin{align*} 1128 \sum\limits_{i,k} \sum_{\substack{i_p,\,k_p}} \Biggl\{ \;\; 1129 \delta_i &\left[ 1130 {e_{2u}}_{i+i_p+1/2}^{k} \;\ \ {A_{e}}_{i+i_p+1/2}^{k} 1131 \ \ \ { _{i+i_p+1/2}^k \mathbb{R}_{-i_p}^{k_p} } \quad \delta_{k+k_p}[T_{i+i_p+1/2}] 1132 \right] \; T_i^k \\ 1133 - \delta_k &\left[ 1134 {e_{2u}}_i^{k+k_p+1/2} \ \ {A_{e}}_i^{k+k_p+1/2} 1135 \ \ { _i^{k+k_p+1/2} \mathbb{R}_{i_p}^{-k_p} } \ \ \delta_{i+i_p}[T^{k+k_p+1/2}] 1136 \right] \; T_i^k \ \Biggr\} 1137 \end{align*} 1138 apply the adjoint of delta operator, it becomes 1139 \begin{align*} 1140 \sum\limits_{i,k} \sum_{\substack{i_p,\,k_p}} \Biggl\{ \;\; 1141 &\left( 1142 {e_{2u}}_{i+i_p+1/2}^{k} \;\ \ {A_{e}}_{i+i_p+1/2}^{k} 1143 \ \ \ { _{i+i_p+1/2}^k \mathbb{R}_{-i_p}^{k_p} } \quad \delta_{k+k_p}[T_{i+i_p+1/2}] 1144 \right) \; \delta_{i+1/2}[T^{k}] \\ 1145 - &\left( 1146 {e_{2u}}_i^{k+k_p+1/2} \ \ {A_{e}}_i^{k+k_p+1/2} 1147 \ \ { _i^{k+k_p+1/2} \mathbb{R}_{i_p}^{-k_p} } \ \ \delta_{i+i_p}[T^{k+k_p+1/2}] 1148 \right) \; \delta_{k+1/2}[T_{i}] \ \Biggr\} 1149 \end{align*} 1150 Expending the summation on $i_p$ and $k_p$, it becomes: 1151 \begin{align*} 1152 \begin{matrix} 1153 &\sum\limits_{i,k} \Bigl\{ 1154 &+{e_{2u}}_{i+1}^{k} &{A_{e}}_{i+1 }^{k} 1155 &\ {_{i+1}^k \mathbb{R}_{- 1/2}^{-1/2}} &\delta_{k-1/2}[T_{i+1}] &\delta_{i+1/2}[T^{k}] &\\ 1156 &&+{e_{2u}}_i^{k\ \ \ \:} &{A_{e}}_{i}^{k\ \ \ \:} 1157 &\ {\ \ \;_i^k \mathbb{R}_{+1/2}^{-1/2}} &\delta_{k-1/2}[T_{i\ \ \ \;}] &\delta_{i+1/2}[T^{k}] &\\ 1158 &&+{e_{2u}}_{i+1}^{k} &{A_{e}}_{i+1 }^{k} 1159 &\ {_{i+1}^k \mathbb{R}_{- 1/2}^{+1/2}} &\delta_{k+1/2}[T_{i+1}] &\delta_{i+1/2}[T^{k}] &\\ 1160 &&+{e_{2u}}_i^{k\ \ \ \:} &{A_{e}}_{i}^{k\ \ \ \:} 1161 &\ {\ \ \;_i^k \mathbb{R}_{+1/2}^{+1/2}} &\delta_{k+1/2}[T_{i\ \ \ \;}] &\delta_{i+1/2}[T^{k}] &\\ 1162 % 1163 &&-{e_{2u}}_i^{k+1} &{A_{e}}_i^{k+1} 1164 &{_i^{k+1} \mathbb{R}_{-1/2}^{- 1/2}} &\delta_{i-1/2}[T^{k+1}] &\delta_{k+1/2}[T_{i}] &\\ 1165 &&-{e_{2u}}_i^{k\ \ \ \:} &{A_{e}}_i^{k\ \ \ \:} 1166 &{\ \ \;_i^k \mathbb{R}_{-1/2}^{+1/2}} &\delta_{i-1/2}[T^{k\ \ \ \:}] &\delta_{k+1/2}[T_{i}] &\\ 1167 &&-{e_{2u}}_i^{k+1 } &{A_{e}}_i^{k+1} 1168 &{_i^{k+1} \mathbb{R}_{+1/2}^{- 1/2}} &\delta_{i+1/2}[T^{k+1}] &\delta_{k+1/2}[T_{i}] &\\ 1169 &&-{e_{2u}}_i^{k\ \ \ \:} &{A_{e}}_i^{k\ \ \ \:} 1170 &{\ \ \;_i^k \mathbb{R}_{+1/2}^{+1/2}} &\delta_{i+1/2}[T^{k\ \ \ \:}] &\delta_{k+1/2}[T_{i}] 1171 &\Bigr\} \\ 1172 \end{matrix} 1173 \end{align*} 1174 The two terms associated with the triad ${_i^k \mathbb{R}_{+1/2}^{+1/2}}$ are the 1175 same but of opposite signs, they cancel out. 1176 Exactly the same thing occurs for the triad ${_i^k \mathbb{R}_{-1/2}^{-1/2}}$. 1177 The two terms associated with the triad ${_i^k \mathbb{R}_{+1/2}^{-1/2}}$ are the 1178 same but both of opposite signs and shifted by 1 in $k$ direction. When summing over $k$ 1179 they cancel out with the neighbouring grid points. 1180 Exactly the same thing occurs for the triad ${_i^k \mathbb{R}_{-1/2}^{+1/2}}$ in the 1181 $i$ direction. Therefore the sum over the domain is zero, $i.e.$ the variance of the 1182 tracer is preserved by the discretisation of the skew fluxes. 1183 1184 %%% Local Variables: 1185 %%% TeX-master: "../../NEMO_book-luatex.tex" 1186 %%% End: 1180 {\psi_1}_{i+1/2}^{k+1/2}={\quarter}\sum_{\substack{i_p,\,k_p}} 1181 {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}. 1182 \end{equation} 1183 The streamfunction $\psi_1$ is calculated similarly at $vw$ points. 1184 The eddy-induced velocities are then calculated from the 1185 straightforward discretisation of \eqref{eq:triad:eiv_v}: 1186 \begin{equation}\label{eq:triad:eiv_v_discrete} 1187 \begin{split} 1188 {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), \\ 1189 {v^*}_{j+1/2}^{k} & = - \frac{1}{{e_{3v}}_{j}^{k}}\left({\psi_2}_{j+1/2}^{k+1/2}-{\psi_2}_{j+1/2}^{k+1/2}\right), \\ 1190 {w^*}_{i,j}^{k+1/2} & = \frac{1}{e_{1t}e_{2t}}\; \left\{ 1191 {e_{2u}}_{i+1/2}^{k+1/2} \,{\psi_1}_{i+1/2}^{k+1/2} - 1192 {e_{2u}}_{i-1/2}^{k+1/2} \,{\psi_1}_{i-1/2}^{k+1/2} \right. + \\ 1193 \phantom{=} & \qquad\qquad\left. {e_{2v}}_{j+1/2}^{k+1/2} \,{\psi_2}_{j+1/2}^{k+1/2} - {e_{2v}}_{j-1/2}^{k+1/2} \,{\psi_2}_{j-1/2}^{k+1/2} \right\}, 1194 \end{split} 1195 \end{equation} -
vendor/nemo/current/DOC/TexFiles/Chapters/Chap_CFG.tex
r1 r4 269 269 270 270 % ------------------------------------------------------------------------------------------------------------- 271 % POMME configuration 272 % ------------------------------------------------------------------------------------------------------------- 273 \section{POMME: mid-latitude sub-domain} 274 \label{MISC_config_POMME} 275 276 277 \key{pomme\_r025} : to be described.... 278 279 280 271 % AMM configuration 272 % ------------------------------------------------------------------------------------------------------------- 273 \section{AMM: atlantic margin configuration (\key{amm\_12km})} 274 \label{MISC_config_AMM} 275 276 The AMM, Atlantic Margins Model, is a regional model covering the 277 Northwest European Shelf domain on a regular lat-lon grid at 278 approximately 12km horizontal resolution. The key \key{amm\_12km} 279 is used to create the correct dimensions of the AMM domain. 280 281 This configuration tests several features of NEMO functionality specific 282 to the shelf seas. 283 In particular, the AMM uses $S$-coordinates in the vertical rather than 284 $z$-coordinates and is forced with tidal lateral boundary conditions 285 using a flather boundary condition from the BDY module (key\_bdy). 286 The AMM configuration uses the GLS (key\_zdfgls) turbulence scheme, the 287 VVL non-linear free surface(key\_vvl) and time-splitting 288 (key\_dynspg\_ts). 289 290 In addition to the tidal boundary condition the model may also take 291 open boundary conditions from a North Atlantic model. Boundaries may be 292 completely ommited by removing the BDY key (key\_bdy). 293 Sample surface fluxes, river forcing and a sample initial restart file 294 are included to test a realistic model run. The Baltic boundary is 295 included within the river input file and is specified as a river source. 296 Unlike ordinary river points the Baltic inputs also include salinity and 297 temperature data. 298 -
vendor/nemo/current/DOC/TexFiles/Chapters/Chap_DIA.tex
r1 r4 943 943 The output format is : 944 944 945 \small{\texttt{date, time-step number, section number, section name, section slope coefficient, class number,945 {\small\texttt{date, time-step number, section number, section name, section slope coefficient, class number, 946 946 class name, class bound 1 , classe bound2, transport\_direction1 , transport\_direction2, transport\_total}}\\ 947 947 -
vendor/nemo/current/DOC/TexFiles/Chapters/Chap_DOM.tex
r1 r4 123 123 the following discrete forms in the curvilinear $s$-coordinate system: 124 124 \begin{equation} \label{Eq_DOM_grad} 125 \nabla q\equiv \frac{1}{e_{1u} } \delta _{i+1/2 } [q] \;\, {\rm {\bf i}}126 + \frac{1}{e_{2v} } \delta _{j+1/2 } [q] \;\, {\rm {\bf j}}127 + \frac{1}{e_{3w}} \delta _{k+1/2} [q] \;\, {\rm {\bf k}}125 \nabla q\equiv \frac{1}{e_{1u} } \delta _{i+1/2 } [q] \;\,\mathbf{i} 126 + \frac{1}{e_{2v} } \delta _{j+1/2 } [q] \;\,\mathbf{j} 127 + \frac{1}{e_{3w}} \delta _{k+1/2} [q] \;\,\mathbf{k} 128 128 \end{equation} 129 129 \begin{multline} \label{Eq_DOM_lap} 130 \Delta q\equiv \frac{1}{e_{1t}\,e_{2t}\,e_{3t} } 130 \Delta q\equiv \frac{1}{e_{1t}\,e_{2t}\,e_{3t} } 131 131 \;\left( \delta_i \left[ \frac{e_{2u}\,e_{3u}} {e_{1u}} \;\delta_{i+1/2} [q] \right] 132 132 + \delta_j \left[ \frac{e_{1v}\,e_{3v}} {e_{2v}} \;\delta_{j+1/2} [q] \right] \; \right) \\ … … 139 139 \begin{eqnarray} \label{Eq_DOM_curl} 140 140 \nabla \times {\rm {\bf A}}\equiv & 141 \frac{1}{e_{2v}\,e_{3vw} } \ \left( \delta_{j +1/2} \left[e_{3w}\,a_3 \right] -\delta_{k+1/2} \left[e_{2v} \,a_2 \right] \right) &\ \ rm{\bfi} \\142 +& \frac{1}{e_{2u}\,e_{3uw}} \ \left( \delta_{k+1/2} \left[e_{1u}\,a_1 \right] -\delta_{i +1/2} \left[e_{3w}\,a_3 \right] \right) &\ \ rm{\bf j} \\143 +& \frac{1}{e_{1f} \,e_{2f} } \ \left( \delta_{i +1/2} \left[e_{2v}\,a_2 \right] -\delta_{j +1/2} \left[e_{1u}\,a_1 \right] \right) &\ \ rm{\bfk}141 \frac{1}{e_{2v}\,e_{3vw} } \ \left( \delta_{j +1/2} \left[e_{3w}\,a_3 \right] -\delta_{k+1/2} \left[e_{2v} \,a_2 \right] \right) &\ \mathbf{i} \\ 142 +& \frac{1}{e_{2u}\,e_{3uw}} \ \left( \delta_{k+1/2} \left[e_{1u}\,a_1 \right] -\delta_{i +1/2} \left[e_{3w}\,a_3 \right] \right) &\ \mathbf{j} \\ 143 +& \frac{1}{e_{1f} \,e_{2f} } \ \left( \delta_{i +1/2} \left[e_{2v}\,a_2 \right] -\delta_{j +1/2} \left[e_{1u}\,a_1 \right] \right) &\ \mathbf{k} 144 144 \end{eqnarray} 145 145 \begin{equation} \label{Eq_DOM_div} -
vendor/nemo/current/DOC/TexFiles/Chapters/Chap_LBC.tex
r1 r4 742 742 743 743 %-----------------------------------------nambdy-------------------------------------------- 744 %- cn_mask = '' ! name of mask file (if ln_bdy_mask=.TRUE.)745 %- cn_dta_frs_T = 'bdydata_grid_T.nc' ! name of data file (T-points)746 %- cn_dta_frs_U = 'bdydata_grid_U.nc' ! name of data file (U-points)747 %- cn_dta_frs_V = 'bdydata_grid_V.nc' ! name of data file (V-points)748 %- cn_dta_fla_T = 'bdydata_bt_grid_T.nc' ! name of data file for Flather condition (T-points)749 %- cn_dta_fla_U = 'bdydata_bt_grid_U.nc' ! name of data file for Flather condition (U-points)750 %- cn_dta_fla_V = 'bdydata_bt_grid_V.nc' ! name of data file for Flather condition (V-points)751 %- ln_clim = .false. ! contain 1 (T) or 12 (F) time dumps and be cyclic752 %- ln_vol = .true. ! total volume correction (see volbdy parameter)753 %- ln_mask = .false. ! boundary mask from filbdy_mask (T) or boundaries are on edges of domain (F)754 %- ln_tides = .true. ! Apply tidal harmonic forcing with Flather condition755 %- ln_dyn_fla = .true. ! Apply Flather condition to velocities756 %- ln_tra_frs = .false. ! Apply FRS condition to temperature and salinity757 %- ln_dyn_frs = .false. ! Apply FRS condition to velocities758 %- nn_rimwidth = 9 ! width of the relaxation zone759 %- nn_dtactl = 1 ! = 0, bdy data are equal to the initial state760 %- ! = 1, bdy data are read in 'bdydata .nc' files761 %- nn_volctl = 0 ! = 0, the total water flux across open boundaries is zero762 %- ! = 1, the total volume of the system is conserved763 744 \namdisplay{nambdy} 745 %----------------------------------------------------------------------------------------------- 746 %-----------------------------------------nambdy_index-------------------------------------------- 747 \namdisplay{nambdy_index} 748 %----------------------------------------------------------------------------------------------- 749 %-----------------------------------------nambdy_dta-------------------------------------------- 750 \namdisplay{nambdy_dta} 751 %----------------------------------------------------------------------------------------------- 752 %-----------------------------------------nambdy_dta-------------------------------------------- 753 \namdisplay{nambdy_dta2} 764 754 %----------------------------------------------------------------------------------------------- 765 755 … … 774 764 The BDY module was modelled on the OBC module and shares many features 775 765 and a similar coding structure \citep{Chanut2005}. 766 767 The BDY module is completely rewritten at NEMO 3.4 and there is a new 768 set of namelists. Boundary data files used with earlier versions of 769 NEMO may need to be re-ordered to work with this version. See the 770 section on the Input Boundary Data Files for details. 771 772 %---------------------------------------------- 773 \subsection{The namelists} 774 \label{BDY_namelist} 775 776 It is possible to define more than one boundary ``set'' and apply 777 different boundary conditions to each set. The number of boundary 778 sets is defined by \np{nb\_bdy}. Each boundary set may be defined 779 as a set of straight line segments in a namelist 780 (\np{ln\_coords\_file}=.false.) or read in from a file 781 (\np{ln\_coords\_file}=.true.). If the set is defined in a namelist, 782 then the namelists nambdy\_index must be included separately, one for 783 each set. If the set is defined by a file, then a 784 ``coordinates.bdy.nc'' file must be provided. The coordinates.bdy file 785 is analagous to the usual NEMO ``coordinates.nc'' file. In the example 786 above, there are two boundary sets, the first of which is defined via 787 a file and the second is defined in a namelist. For more details of 788 the definition of the boundary geometry see section 789 \ref{BDY_geometry}. 790 791 For each boundary set a boundary 792 condition has to be chosen for the barotropic solution (``u2d'': 793 sea-surface height and barotropic velocities), for the baroclinic 794 velocities (``u3d''), and for the active tracers\footnote{The BDY 795 module does not deal with passive tracers at this version} 796 (``tra''). For each set of variables there is a choice of algorithm 797 and a choice for the data, eg. for the active tracers the algorithm is 798 set by \np{nn\_tra} and the choice of data is set by 799 \np{nn\_tra\_dta}. 800 801 The choice of algorithm is currently as follows: 802 803 \mbox{} 804 805 \begin{itemize} 806 \item[0.] No boundary condition applied. So the solution will ``see'' 807 the land points around the edge of the edge of the domain. 808 \item[1.] Flow Relaxation Scheme (FRS) available for all variables. 809 \item[2.] Flather radiation scheme for the barotropic variables. The 810 Flather scheme is not compatible with the filtered free surface 811 ({\it dynspg\_ts}). 812 \end{itemize} 813 814 \mbox{} 815 816 The main choice for the boundary data is 817 to use initial conditions as boundary data (\np{nn\_tra\_dta}=0) or to 818 use external data from a file (\np{nn\_tra\_dta}=1). For the 819 barotropic solution there is also the option to use tidal 820 harmonic forcing either by itself or in addition to other external 821 data. 822 823 If external boundary data is required then the nambdy\_dta namelist 824 must be defined. One nambdy\_dta namelist is required for each boundary 825 set in the order in which the boundary sets are defined in nambdy. In 826 the example given, two boundary sets have been defined and so there 827 are two nambdy\_dta namelists. The boundary data is read in using the 828 fldread module, so the nambdy\_dta namelist is in the format required 829 for fldread. For each variable required, the filename, the frequency 830 of the files and the frequency of the data in the files is given. Also 831 whether or not time-interpolation is required and whether the data is 832 climatological (time-cyclic) data. Note that on-the-fly spatial 833 interpolation of boundary data is not available at this version. 834 835 In the example namelists given, two boundary sets are defined. The 836 first set is defined via a file and applies FRS conditions to 837 temperature and salinity and Flather conditions to the barotropic 838 variables. External data is provided in daily files (from a 839 large-scale model). Tidal harmonic forcing is also used. The second 840 set is defined in a namelist. FRS conditions are applied on 841 temperature and salinity and climatological data is read from external 842 files. 776 843 777 844 %---------------------------------------------- … … 832 899 Note that the sea-surface height gradient in \eqref{Eq_bdy_fla1} 833 900 is a spatial gradient across the model boundary, so that $\eta_{e}$ is 834 defined on the $T$ points with $nbrdta=1$ and $\eta$ is defined on the 835 $T$ points with $nbrdta=2$. $U$ and $U_{e}$ are defined on the $U$ or 836 $V$ points with $nbrdta=1$, $i.e.$ between the two $T$ grid points. 837 838 %---------------------------------------------- 839 \subsection{Choice of schemes} 840 \label{BDY_choice_of_schemes} 841 842 The Flow Relaxation Scheme may be applied separately to the 843 temperature and salinity (\np{ln\_tra\_frs} = true) and 844 the velocity fields (\np{ln\_dyn\_frs} = true). Flather 845 radiation conditions may be applied using externally defined 846 barotropic velocities and sea-surface height (\np{ln\_dyn\_fla} = true) 847 or using tidal harmonics fields (\np{ln\_tides} = true) 848 or both. FRS and Flather conditions may be applied simultaneously. 849 A typical configuration where all possible conditions might be used is a tidal, 850 shelf-seas model, where the barotropic boundary conditions are fixed 851 with the Flather scheme using tidal harmonics and possibly output 852 from a large-scale model, and FRS conditions are applied to the tracers 853 and baroclinic velocity fields, using fields from a large-scale model. 854 855 Note that FRS conditions will work with the filtered 856 (\key{dynspg\_flt}) or time-split (\key{dynspg\_ts}) solutions for the 857 surface pressure gradient. The Flather condition will only work for 858 the time-split solution (\key{dynspg\_ts}). FRS conditions are applied 859 at the end of the main model time step. Flather conditions are applied 860 during the barotropic subcycle in the time-split solution. 901 defined on the $T$ points with $nbr=1$ and $\eta$ is defined on the 902 $T$ points with $nbr=2$. $U$ and $U_{e}$ are defined on the $U$ or 903 $V$ points with $nbr=1$, $i.e.$ between the two $T$ grid points. 861 904 862 905 %---------------------------------------------- … … 864 907 \label{BDY_geometry} 865 908 866 The definition of the open boundary is completely flexible. An example 867 is shown in Fig.~\ref{Fig_LBC_bdy_geom}. The boundary zone is 868 defined by a series of index arrays read in from the input boundary 869 data files: $nbidta$, $nbjdta$, and $nbrdta$. The first two of these 870 define the global $(i,j)$ indices of each point in the boundary zone 871 and the $nbrdta$ array defines the discrete distance from the boundary 872 with $nbrdta=1$ meaning that the point is next to the edge of the 873 model domain and $nbrdta>1$ showing that the point is increasingly 874 further away from the edge of the model domain. These arrays are 875 defined separately for each of the $T$, $U$ and $V$ grids, but the 876 relationship between the points is assumed to be as in Fig. 877 \ref{Fig_LBC_bdy_geom} with the $T$ points forming the outermost row 878 of the boundary and the first row of velocities normal to the boundary 879 being inside the first row of $T$ points. The order in which the 880 points are defined is unimportant. 909 Each open boundary set is defined as a list of points. The information 910 is stored in the arrays $nbi$, $nbj$, and $nbr$ in the $idx\_bdy$ 911 structure. The $nbi$ and $nbj$ arrays 912 define the local $(i,j)$ indices of each point in the boundary zone 913 and the $nbr$ array defines the discrete distance from the boundary 914 with $nbr=1$ meaning that the point is next to the edge of the 915 model domain and $nbr>1$ showing that the point is increasingly 916 further away from the edge of the model domain. A set of $nbi$, $nbj$, 917 and $nbr$ arrays is defined for each of the $T$, $U$ and $V$ 918 grids. Figure \ref{Fig_LBC_bdy_geom} shows an example of an irregular 919 boundary. 920 921 The boundary geometry for each set may be defined in a namelist 922 nambdy\_index or by reading in a ``coordinates.bdy.nc'' file. The 923 nambdy\_index namelist defines a series of straight-line segments for 924 north, east, south and west boundaries. For the northern boundary, 925 \np{nbdysegn} gives the number of segments, \np{jpjnob} gives the $j$ 926 index for each segment and \np{jpindt} and \np{jpinft} give the start 927 and end $i$ indices for each segment with similar for the other 928 boundaries. These segments define a list of $T$ grid points along the 929 outermost row of the boundary ($nbr\,=\, 1$). The code deduces the $U$ and 930 $V$ points and also the points for $nbr\,>\, 1$ if 931 $nn\_rimwidth\,>\,1$. 932 933 The boundary geometry may also be defined from a 934 ``coordinates.bdy.nc'' file. Figure \ref{Fig_LBC_nc_header} 935 gives an example of the header information from such a file. The file 936 should contain the index arrays for each of the $T$, $U$ and $V$ 937 grids. The arrays must be in order of increasing $nbr$. Note that the 938 $nbi$, $nbj$ values in the file are global values and are converted to 939 local values in the code. Typically this file will be used to generate 940 external boundary data via interpolation and so will also contain the 941 latitudes and longitudes of each point as shown. However, this is not 942 necessary to run the model. 943 944 For some choices of irregular boundary the model domain may contain 945 areas of ocean which are not part of the computational domain. For 946 example if an open boundary is defined along an isobath, say at the 947 shelf break, then the areas of ocean outside of this boundary will 948 need to be masked out. This can be done by reading a mask file defined 949 as \np{cn\_mask\_file} in the nam\_bdy namelist. Only one mask file is 950 used even if multiple boundary sets are defined. 881 951 882 952 %>>>>>>>>>>>>>>>>>>>>>>>>>>>> … … 892 962 \label{BDY_data} 893 963 894 The input data files for the FRS conditions are defined in the 895 namelist as \np{cn\_dta\_frs\_T}, \np{cn\_dta\_frs\_U}, 896 \np{cn\_dta\_frs\_V}. The input data files for the Flather conditions 897 are defined in the namelist as \np{cn\_dta\_fla\_T}, 898 \np{cn\_dta\_fla\_U}, \np{cn\_dta\_fla\_V}. 899 900 The netcdf header of a typical input data file is shown in Fig.~\ref{Fig_LBC_nc_header}. 901 The file contains the index arrays which define the boundary geometry 902 as noted above and the data arrays for each field. 903 The data arrays are dimensioned on: a time dimension; $xb$ 904 which is the index of the boundary data point in the horizontal; 905 and $yb$ which is a degenerate dimension of 1 to enable 906 the file to be read by the standard NEMO I/O routines. The 3D fields 907 also have a depth dimension. 908 909 If \np{ln\_clim} is set to \textit{false}, the model expects the 910 units of the time axis to have the form shown in 911 Fig.~\ref{Fig_LBC_nc_header}, $i.e.$ {\it ``seconds since yyyy-mm-dd 912 hh:mm:ss''} The fields are then linearly interpolated to the model 913 time at each timestep. Note that for this option, the time axis of the 914 input files must completely span the time period of the model 915 integration. If \np{ln\_clim} is set to \textit{true} (climatological 916 boundary forcing), the model will expect either a single set of annual 917 mean fields (constant boundary forcing) or 12 sets of monthly mean 918 fields in the input files. 919 920 As in the OBC module there is an option to use initial conditions as 921 boundary conditions. This is chosen by setting 922 \np{nn\_dtactl}~=~0. However, since the model defines the boundary 923 geometry by reading the boundary index arrays from the input files, 924 it is still necessary to provide a set of input files in this 925 case. They need only contain the boundary index arrays, $nbidta$, 926 \textit{nbjdta}, \textit{nbrdta}. 964 The data files contain the data arrays 965 in the order in which the points are defined in the $nbi$ and $nbj$ 966 arrays. The data arrays are dimensioned on: a time dimension; 967 $xb$ which is the index of the boundary data point in the horizontal; 968 and $yb$ which is a degenerate dimension of 1 to enable the file to be 969 read by the standard NEMO I/O routines. The 3D fields also have a 970 depth dimension. 971 972 At Version 3.4 there are new restrictions on the order in which the 973 boundary points are defined (and therefore restrictions on the order 974 of the data in the file). In particular: 975 976 \mbox{} 977 978 \begin{enumerate} 979 \item The data points must be in order of increasing $nbr$, ie. all 980 the $nbr=1$ points, then all the $nbr=2$ points etc. 981 \item All the data for a particular boundary set must be in the same 982 order. (Prior to 3.4 it was possible to define barotropic data in a 983 different order to the data for tracers and baroclinic velocities). 984 \end{enumerate} 985 986 \mbox{} 987 988 These restrictions mean that data files used with previous versions of 989 the model may not work with version 3.4. A fortran utility 990 {\it bdy\_reorder} exists in the TOOLS directory which will re-order the 991 data in old BDY data files. 927 992 928 993 %>>>>>>>>>>>>>>>>>>>>>>>>>>>> … … 930 995 \includegraphics[width=1.0\textwidth]{./TexFiles/Figures/Fig_LBC_nc_header.pdf} 931 996 \caption { \label{Fig_LBC_nc_header} 932 Example of header of netcdf input data file for BDY}997 Example of the header for a coordinates.bdy.nc file} 933 998 \end{center} \end{figure} 934 999 %>>>>>>>>>>>>>>>>>>>>>>>>>>>> … … 940 1005 There is an option to force the total volume in the regional model to be constant, 941 1006 similar to the option in the OBC module. This is controlled by the \np{nn\_volctl} 942 parameter in the namelist. A value of \np{nn\_volctl}~=~0 indicates that this option is not used.1007 parameter in the namelist. A value of \np{nn\_volctl}~=~0 indicates that this option is not used. 943 1008 If \np{nn\_volctl}~=~1 then a correction is applied to the normal velocities 944 1009 around the boundary at each timestep to ensure that the integrated volume flow … … 947 1012 flux across the surface and the correction velocity corrects for this as well. 948 1013 949 1014 If more than one boundary set is used then volume correction is 1015 applied to all boundaries at once. 1016 1017 \newpage 950 1018 %---------------------------------------------- 951 1019 \subsection{Tidal harmonic forcing} 952 1020 \label{BDY_tides} 953 1021 1022 %-----------------------------------------nambdy_tide-------------------------------------------- 1023 \namdisplay{nambdy_tide} 1024 %----------------------------------------------------------------------------------------------- 1025 954 1026 To be written.... 955 1027 -
vendor/nemo/current/DOC/TexFiles/Chapters/Chap_LDF.tex
r1 r4 21 21 and for tracers only, eddy induced advection on tracers). These three aspects 22 22 of the lateral diffusion are set through namelist parameters and CPP keys 23 (see the \textit{nam\_traldf} and \textit{nam\_dynldf} below). 23 (see the \textit{nam\_traldf} and \textit{nam\_dynldf} below). Note 24 that this chapter describes the default implementation of iso-neutral 25 tracer mixing, and Griffies's implementation, which is used if 26 \np{traldf\_grif}=true, is described in Appdx\ref{sec:triad} 24 27 25 28 %-----------------------------------nam_traldf - nam_dynldf-------------------------------------------- … … 128 131 $\ $\newline % force a new ligne 129 132 130 A space variation in the eddy coefficient appeals several remarks:133 The following points are relevant when the eddy coefficient varies spatially: 131 134 132 135 (1) the momentum diffusion operator acting along model level surfaces is 133 136 written in terms of curl and divergent components of the horizontal current 134 (see \S\ref{PE_ldf}). Although the eddy coefficient c anbe set to different values135 in these two terms, this option is not available.137 (see \S\ref{PE_ldf}). Although the eddy coefficient could be set to different values 138 in these two terms, this option is not currently available. 136 139 137 140 (2) with an horizontally varying viscosity, the quadratic integral constraints … … 275 278 276 279 \item[$s$- or hybrid $s$-$z$- coordinate : ] in the current release of \NEMO, 277 there is no specific treatment for iso-neutral mixing in the $s$-coordinate. 280 iso-neutral mixing is only employed for $s$-coordinates if the 281 Griffies scheme is used (\np{traldf\_grif}=true; see Appdx \ref{sec:triad}). 278 282 In other words, iso-neutral mixing will only be accurately represented with a 279 283 linear equation of state (\np{nn\_eos}=1 or 2). In the case of a "true" equation … … 332 336 \end{description} 333 337 334 This implementation is a rather old one. It is similar to the one proposed 335 by Cox [1987], except for the background horizontal diffusion. Indeed, 336 the Cox implementation of isopycnal diffusion in GFDL-type models requires 337 a minimum background horizontal diffusion for numerical stability reasons. 338 To overcome this problem, several techniques have been proposed in which 339 the numerical schemes of the ocean model are modified \citep{Weaver_Eby_JPO97, 340 Griffies_al_JPO98}. Here, another strategy has been chosen \citep{Lazar_PhD97}: 341 a local filtering of the iso-neutral slopes (made on 9 grid-points) prevents 342 the development of grid point noise generated by the iso-neutral diffusion 343 operator (Fig.~\ref{Fig_LDF_ZDF1}). This allows an iso-neutral diffusion scheme 344 without additional background horizontal mixing. This technique can be viewed 345 as a diffusion operator that acts along large-scale (2~$\Delta$x) 346 \gmcomment{2deltax doesnt seem very large scale} 347 iso-neutral surfaces. The diapycnal diffusion required for numerical stability is 348 thus minimized and its net effect on the flow is quite small when compared to 349 the effect of an horizontal background mixing. 338 This implementation is a rather old one. It is similar to the one 339 proposed by Cox [1987], except for the background horizontal 340 diffusion. Indeed, the Cox implementation of isopycnal diffusion in 341 GFDL-type models requires a minimum background horizontal diffusion 342 for numerical stability reasons. To overcome this problem, several 343 techniques have been proposed in which the numerical schemes of the 344 ocean model are modified \citep{Weaver_Eby_JPO97, 345 Griffies_al_JPO98}. Griffies's scheme is now available in \NEMO if 346 \np{traldf\_grif\_iso} is set true; see Appdx \ref{sec:triad}. Here, 347 another strategy is presented \citep{Lazar_PhD97}: a local 348 filtering of the iso-neutral slopes (made on 9 grid-points) prevents 349 the development of grid point noise generated by the iso-neutral 350 diffusion operator (Fig.~\ref{Fig_LDF_ZDF1}). This allows an 351 iso-neutral diffusion scheme without additional background horizontal 352 mixing. This technique can be viewed as a diffusion operator that acts 353 along large-scale (2~$\Delta$x) \gmcomment{2deltax doesnt seem very 354 large scale} iso-neutral surfaces. The diapycnal diffusion required 355 for numerical stability is thus minimized and its net effect on the 356 flow is quite small when compared to the effect of an horizontal 357 background mixing. 350 358 351 359 Nevertheless, this iso-neutral operator does not ensure that variance cannot increase, -
vendor/nemo/current/DOC/TexFiles/Chapters/Chap_TRA.tex
r1 r4 491 491 \label{TRA_ldf_iso} 492 492 493 The general form of the second order lateral tracer subgrid scale physics 493 If the Griffies trad scheme is not employed 494 (\np{ln\_traldf\_grif}=true; see App.\ref{sec:triad}) the general form of the second order lateral tracer subgrid scale physics 494 495 (\ref{Eq_PE_zdf}) takes the following semi-discrete space form in $z$- and 495 496 $s$-coordinates: … … 536 537 (see \S\ref{LDF}) allows the model to run safely without any additional 537 538 background horizontal diffusion \citep{Guilyardi_al_CD01}. An alternative scheme 538 developed by \cite{Griffies_al_JPO98} which preserves both tracer and its variance539 developed by \cite{Griffies_al_JPO98} which ensures tracer variance decreases 539 540 is also available in \NEMO (\np{ln\_traldf\_grif}=true). A complete description of 540 the algorithm is given in App.\ref{ Apdx_Griffies}.541 the algorithm is given in App.\ref{sec:triad}. 541 542 542 543 Note that in the partial step $z$-coordinate (\np{ln\_zps}=true), the horizontal -
vendor/nemo/current/DOC/TexFiles/Chapters/Introduction.tex
r1 r4 202 202 concern of improving the model performance. 203 203 204 \vspace{1cm} 205 $\bullet$ The main modifications from NEMO/OPA v3.3 and v3.4 are :\\ 206 \begin{enumerate} 207 \item finalisation of above iso-neutral mixing \citep{Griffies_al_JPO98}"; 208 \item "Neptune effect" parametrisation; 209 \item horizontal pressure gradient suitable for s-coordinate; 210 \item semi-implicit bottom friction; 211 \item finalisation of the merge of passive and active tracers advection-diffusion modules; 212 \item a new bulk formulae (so-called MFS); 213 \item use fldread for the off-line tracer component (OFF\_SRC) ; 214 \item use MPI point to point communications for north fold; 215 \item diagnostic of transport ; 216 \end{enumerate} 217 218 -
vendor/nemo/current/DOC/TexFiles/Namelist/nambdy
r1 r4 2 2 &nambdy ! unstructured open boundaries ("key_bdy") 3 3 !----------------------------------------------------------------------- 4 cn_mask = '' ! name of mask file (ln_mask=T) 5 cn_dta_frs_T= 'bdydata_grid_T.nc' ! name of data file (T-points) 6 cn_dta_frs_U= 'bdydata_grid_U.nc' ! name of data file (U-points) 7 cn_dta_frs_V= 'bdydata_grid_V.nc' ! name of data file (V-points) 8 cn_dta_fla_T= 'bdydata_bt_grid_T.nc' ! name of data file for Flather condition (T-points) 9 cn_dta_fla_U= 'bdydata_bt_grid_U.nc' ! name of data file for Flather condition (U-points) 10 cn_dta_fla_V= 'bdydata_bt_grid_V.nc' ! name of data file for Flather condition (V-points) 11 12 ln_clim = .false. ! contain 1 (T) or 12 (F) time dumps and be cyclic 13 ln_vol = .false. ! total volume correction (see volbdy parameter) 14 ln_mask = .false. ! boundary mask from filbdy_mask (T), boundaries are on edges of domain (F) 15 ln_tides = .false. ! Apply tidal harmonic forcing with Flather condition 16 ln_dyn_fla = .false. ! Apply Flather condition to velocities 17 ln_tra_frs = .false. ! Apply FRS condition to temperature and salinity 18 ln_dyn_frs = .false. ! Apply FRS condition to velocities 19 nn_rimwidth = 9 ! width of the relaxation zone 20 nn_dtactl = 1 ! = 0, bdy data are equal to the initial state 21 ! = 1, bdy data are read in 'bdydata .nc' files 22 nn_volctl = 0 ! = 0, the total water flux across open boundaries is zero 23 ! = 1, the total volume of the system is conserved 4 nb_bdy = 2 ! number of open boundary sets 5 ln_coords_file = .true.,.false. ! =T : read bdy coordinates from file 6 cn_coords_file = 'coordinates.bdy.nc','' ! bdy coordinates files 7 ln_mask_file = .false. ! =T : read mask from file 8 cn_mask_file = '' ! name of mask file (if ln_mask_file=.TRUE.) 9 nn_dyn2d = 2, 0 ! boundary conditions for barotropic fields 10 nn_dyn2d_dta = 3, 0 ! = 0, bdy data are equal to the initial state 11 ! = 1, bdy data are read in 'bdydata .nc' files 12 ! = 2, use tidal harmonic forcing data from files 13 ! = 3, use external data AND tidal harmonic forcing 14 nn_dyn3d = 0, 0 ! boundary conditions for baroclinic velocities 15 nn_dyn3d_dta = 0, 0 ! = 0, bdy data are equal to the initial state 16 ! = 1, bdy data are read in 'bdydata .nc' files 17 nn_tra = 1, 1 ! boundary conditions for T and S 18 nn_tra_dta = 1, 1 ! = 0, bdy data are equal to the initial state 19 ! = 1, bdy data are read in 'bdydata .nc' files 20 nn_rimwidth = 10, 5 ! width of the relaxation zone 21 ln_vol = .false. ! total volume correction (see nn_volctl parameter) 22 nn_volctl = 1 ! = 0, the total water flux across open boundaries is zero 24 23 / -
vendor/nemo/current/DOC/TexFiles/Namelist/nambdy_tide
r1 r4 1 1 !----------------------------------------------------------------------- 2 &nambdy_tide ! tidal forcing at unstructuredboundaries2 &nambdy_tide ! tidal forcing at open boundaries 3 3 !----------------------------------------------------------------------- 4 filtide = 'bdytide_' ! file name root of tidal forcing files 5 tide_cpt = 'M2','S1' ! names of tidal components used 6 tide_speed = 28.984106, 15.000001 ! phase speeds of tidal components (deg/hour) 7 ln_tide_date= .false. ! adjust tidal harmonics for start date of run 4 filtide = 'bdydta/amm12_bdytide_' ! file name root of tidal forcing files 5 tide_cpt(1) ='Q1' ! names of tidal components used 6 tide_cpt(2) ='O1' ! names of tidal components used 7 tide_cpt(3) ='P1' ! names of tidal components used 8 tide_cpt(4) ='S1' ! names of tidal components used 9 tide_cpt(5) ='K1' ! names of tidal components used 10 tide_cpt(6) ='2N2' ! names of tidal components used 11 tide_cpt(7) ='MU2' ! names of tidal components used 12 tide_cpt(8) ='N2' ! names of tidal components used 13 tide_cpt(9) ='NU2' ! names of tidal components used 14 tide_cpt(10) ='M2' ! names of tidal components used 15 tide_cpt(11) ='L2' ! names of tidal components used 16 tide_cpt(12) ='T2' ! names of tidal components used 17 tide_cpt(13) ='S2' ! names of tidal components used 18 tide_cpt(14) ='K2' ! names of tidal components used 19 tide_cpt(15) ='M4' ! names of tidal components used 20 tide_speed(1) = 13.398661 ! phase speeds of tidal components (deg/hour) 21 tide_speed(2) = 13.943036 ! phase speeds of tidal components (deg/hour) 22 tide_speed(3) = 14.958932 ! phase speeds of tidal components (deg/hour) 23 tide_speed(4) = 15.000001 ! phase speeds of tidal components (deg/hour) 24 tide_speed(5) = 15.041069 ! phase speeds of tidal components (deg/hour) 25 tide_speed(6) = 27.895355 ! phase speeds of tidal components (deg/hour) 26 tide_speed(7) = 27.968210 ! phase speeds of tidal components (deg/hour) 27 tide_speed(8) = 28.439730 ! phase speeds of tidal components (deg/hour) 28 tide_speed(9) = 28.512585 ! phase speeds of tidal components (deg/hour) 29 tide_speed(10) = 28.984106 ! phase speeds of tidal components (deg/hour) 30 tide_speed(11) = 29.528479 ! phase speeds of tidal components (deg/hour) 31 tide_speed(12) = 29.958935 ! phase speeds of tidal components (deg/hour) 32 tide_speed(13) = 30.000002 ! phase speeds of tidal components (deg/hour) 33 tide_speed(14) = 30.082138 ! phase speeds of tidal components (deg/hour) 34 tide_speed(15) = 57.968212 ! phase speeds of tidal components (deg/hour) 35 ln_tide_date = .true. ! adjust tidal harmonics for start date of run 8 36 / -
vendor/nemo/current/DOC/TexFiles/Namelist/namtra_ldf
r1 r4 1 !----------------------------------------------------------------------- 2 &namtra_ldf ! lateral diffusion scheme for tracer 3 !----------------------------------------------------------------------- 4 ! ! Type of the operator:1 !---------------------------------------------------------------------------------- 2 &namtra_ldf ! lateral diffusion scheme for tracers 3 !---------------------------------------------------------------------------------- 4 ! ! Operator type: 5 5 ln_traldf_lap = .true. ! laplacian operator 6 6 ln_traldf_bilap = .false. ! bilaplacian operator 7 ! ! Direction of action 7 ! ! Direction of action: 8 8 ln_traldf_level = .false. ! iso-level 9 ln_traldf_hor = .false. ! horizontal (geopotential) (requires "key_ldfslp" when ln_sco=T)10 ln_traldf_iso = .true. ! iso-neutral (requires "key_ldfslp")11 ! ! Griffies parameters 12 ln_traldf_grif = .false. ! use griffies triad formulation (requires "key_ldfslp")13 ln_traldf_gdia = .false. ! output griffies strfn diagnostics (requires "key_ldfslp")14 ln_triad_iso = .false. ! isoneutral diff'n triads => pure lateral mixing in ML (requires "key_ldfslp")15 ln_botmix_grif = .false. ! griffies operator with lateral mixing on bottom (requires "key_ldfslp")9 ln_traldf_hor = .false. ! horizontal (geopotential) (needs "key_ldfslp" when ln_sco=T) 10 ln_traldf_iso = .true. ! iso-neutral (needs "key_ldfslp") 11 ! ! Griffies parameters (all need "key_ldfslp") 12 ln_traldf_grif = .false. ! use griffies triads 13 ln_traldf_gdia = .false. ! output griffies eddy velocities 14 ln_triad_iso = .false. ! pure lateral mixing in ML 15 ln_botmix_grif = .false. ! lateral mixing on bottom 16 16 ! ! Coefficients 17 ! rn_aeiv_0 is ignored with Held-Larichev spatially varying aeiv (key_traldf_c2d & key_orca_r2, _r1 or _r05) 18 rn_aeiv_0 = 2000. ! eddy induced velocity coefficient [m2/s] (requires "key_traldf_eiv") 17 ! Eddy-induced (GM) advection always used with Griffies; otherwise needs "key_traldf_eiv" 18 ! Value rn_aeiv_0 is ignored unless = 0 with Held-Larichev spatially varying aeiv 19 ! (key_traldf_c2d & key_traldf_eiv & key_orca_r2, _r1 or _r05) 20 rn_aeiv_0 = 2000. ! eddy induced velocity coefficient [m2/s] 19 21 rn_aht_0 = 2000. ! horizontal eddy diffusivity for tracers [m2/s] 20 rn_ahtb_0 = 0. ! background eddy diffusivity for ldf_iso [m2/s] (normally=0; not used with Griffies) 22 rn_ahtb_0 = 0. ! background eddy diffusivity for ldf_iso [m2/s] 23 ! (normally=0; not used with Griffies) 21 24 / -
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