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Changeset 11692 for NEMO/branches/2019/dev_r11514_HPC-02_single-core-extrahalo/doc/latex/NEMO/subfiles/chap_LDF.tex – NEMO

Ignore:
Timestamp:
2019-10-12T16:08:18+02:00 (5 years ago)
Author:
francesca
Message:

Update branch to integrate the development starting from the current v4.01 ready trunk

Location:
NEMO/branches/2019/dev_r11514_HPC-02_single-core-extrahalo/doc
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5 edited

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  • NEMO/branches/2019/dev_r11514_HPC-02_single-core-extrahalo/doc/latex/NEMO/subfiles/chap_LDF.tex

    r11435 r11692  
    33\begin{document} 
    44 
    5 % ================================================================ 
    6 % Chapter Lateral Ocean Physics (LDF) 
    7 % ================================================================ 
    85\chapter{Lateral Ocean Physics (LDF)} 
    96\label{chap:LDF} 
    107 
     8\thispagestyle{plain} 
     9 
    1110\chaptertoc 
    1211 
    13 \newpage 
    14  
    15 The lateral physics terms in the momentum and tracer equations have been described in \autoref{eq:PE_zdf} and 
     12\paragraph{Changes record} ~\\ 
     13 
     14{\footnotesize 
     15  \begin{tabularx}{\textwidth}{l||X|X} 
     16    Release & Author(s) & Modifications \\ 
     17    \hline 
     18    {\em   4.0} & {\em ...} & {\em ...} \\ 
     19    {\em   3.6} & {\em ...} & {\em ...} \\ 
     20    {\em   3.4} & {\em ...} & {\em ...} \\ 
     21    {\em <=3.4} & {\em ...} & {\em ...} 
     22  \end{tabularx} 
     23} 
     24 
     25\clearpage 
     26 
     27The lateral physics terms in the momentum and tracer equations have been described in \autoref{eq:MB_zdf} and 
    1628their discrete formulation in \autoref{sec:TRA_ldf} and \autoref{sec:DYN_ldf}). 
    1729In this section we further discuss each lateral physics option. 
     
    2234(3) the space and time variations of the eddy coefficients. 
    2335These three aspects of the lateral diffusion are set through namelist parameters 
    24 (see the \nam{tra\_ldf} and \nam{dyn\_ldf} below). 
    25 Note that this chapter describes the standard implementation of iso-neutral tracer mixing.  
    26 Griffies's implementation, which is used if \np{ln\_traldf\_triad}\forcode{ = .true.}, 
    27 is described in \autoref{apdx:triad} 
    28  
    29 %-----------------------------------namtra_ldf - namdyn_ldf-------------------------------------------- 
    30  
    31 \nlst{namtra_ldf}  
    32  
    33 \nlst{namdyn_ldf}  
    34 %-------------------------------------------------------------------------------------------------------------- 
    35  
    36 % ================================================================ 
    37 % Lateral Mixing Operator 
    38 % ================================================================ 
    39 \section[Lateral mixing operators] 
    40 {Lateral mixing operators} 
     36(see the \nam{tra_ldf}{tra\_ldf} and \nam{dyn_ldf}{dyn\_ldf} below). 
     37Note that this chapter describes the standard implementation of iso-neutral tracer mixing. 
     38Griffies's implementation, which is used if \np[=.true.]{ln_traldf_triad}{ln\_traldf\_triad}, 
     39is described in \autoref{apdx:TRIADS} 
     40 
     41%% ================================================================================================= 
     42\section[Lateral mixing operators]{Lateral mixing operators} 
    4143\label{sec:LDF_op} 
    4244We remind here the different lateral mixing operators that can be used. Further details can be found in \autoref{subsec:TRA_ldf_op} and  \autoref{sec:DYN_ldf}. 
    4345 
    44 \subsection[No lateral mixing (\forcode{ln_traldf_OFF}, \forcode{ln_dynldf_OFF})] 
    45 {No lateral mixing (\protect\np{ln\_traldf\_OFF}, \protect\np{ln\_dynldf\_OFF})} 
    46  
    47 It is possible to run without explicit lateral diffusion on tracers (\protect\np{ln\_traldf\_OFF}\forcode{ = .true.}) and/or  
    48 momentum (\protect\np{ln\_dynldf\_OFF}\forcode{ = .true.}). The latter option is even recommended if using the  
    49 UBS advection scheme on momentum (\np{ln\_dynadv\_ubs}\forcode{ = .true.}, 
     46%% ================================================================================================= 
     47\subsection[No lateral mixing (\forcode{ln_traldf_OFF} \& \forcode{ln_dynldf_OFF})]{No lateral mixing (\protect\np{ln_traldf_OFF}{ln\_traldf\_OFF} \& \protect\np{ln_dynldf_OFF}{ln\_dynldf\_OFF})} 
     48 
     49It is possible to run without explicit lateral diffusion on tracers (\protect\np[=.true.]{ln_traldf_OFF}{ln\_traldf\_OFF}) and/or 
     50momentum (\protect\np[=.true.]{ln_dynldf_OFF}{ln\_dynldf\_OFF}). The latter option is even recommended if using the 
     51UBS advection scheme on momentum (\np[=.true.]{ln_dynadv_ubs}{ln\_dynadv\_ubs}, 
    5052see \autoref{subsec:DYN_adv_ubs}) and can be useful for testing purposes. 
    5153 
    52 \subsection[Laplacian mixing (\forcode{ln_traldf_lap}, \forcode{ln_dynldf_lap})] 
    53 {Laplacian mixing (\protect\np{ln\_traldf\_lap}, \protect\np{ln\_dynldf\_lap})} 
    54 Setting \protect\np{ln\_traldf\_lap}\forcode{ = .true.} and/or \protect\np{ln\_dynldf\_lap}\forcode{ = .true.} enables  
    55 a second order diffusion on tracers and momentum respectively. Note that in \NEMO\ 4, one can not combine  
     54%% ================================================================================================= 
     55\subsection[Laplacian mixing (\forcode{ln_traldf_lap} \& \forcode{ln_dynldf_lap})]{Laplacian mixing (\protect\np{ln_traldf_lap}{ln\_traldf\_lap} \& \protect\np{ln_dynldf_lap}{ln\_dynldf\_lap})} 
     56Setting \protect\np[=.true.]{ln_traldf_lap}{ln\_traldf\_lap} and/or \protect\np[=.true.]{ln_dynldf_lap}{ln\_dynldf\_lap} enables 
     57a second order diffusion on tracers and momentum respectively. Note that in \NEMO\ 4, one can not combine 
    5658Laplacian and Bilaplacian operators for the same variable. 
    5759 
    58 \subsection[Bilaplacian mixing (\forcode{ln_traldf_blp}, \forcode{ln_dynldf_blp})] 
    59 {Bilaplacian mixing (\protect\np{ln\_traldf\_blp}, \protect\np{ln\_dynldf\_blp})} 
    60 Setting \protect\np{ln\_traldf\_blp}\forcode{ = .true.} and/or \protect\np{ln\_dynldf\_blp}\forcode{ = .true.} enables  
    61 a fourth order diffusion on tracers and momentum respectively. It is implemented by calling the above Laplacian operator twice.  
     60%% ================================================================================================= 
     61\subsection[Bilaplacian mixing (\forcode{ln_traldf_blp} \& \forcode{ln_dynldf_blp})]{Bilaplacian mixing (\protect\np{ln_traldf_blp}{ln\_traldf\_blp} \& \protect\np{ln_dynldf_blp}{ln\_dynldf\_blp})} 
     62Setting \protect\np[=.true.]{ln_traldf_blp}{ln\_traldf\_blp} and/or \protect\np[=.true.]{ln_dynldf_blp}{ln\_dynldf\_blp} enables 
     63a fourth order diffusion on tracers and momentum respectively. It is implemented by calling the above Laplacian operator twice. 
    6264We stress again that from \NEMO\ 4, the simultaneous use Laplacian and Bilaplacian operators is not allowed. 
    6365 
    64 % ================================================================ 
    65 % Direction of lateral Mixing 
    66 % ================================================================ 
    67 \section[Direction of lateral mixing (\textit{ldfslp.F90})] 
    68 {Direction of lateral mixing (\protect\mdl{ldfslp})} 
     66%% ================================================================================================= 
     67\section[Direction of lateral mixing (\textit{ldfslp.F90})]{Direction of lateral mixing (\protect\mdl{ldfslp})} 
    6968\label{sec:LDF_slp} 
    7069 
    71 %%% 
    7270\gmcomment{ 
    7371  we should emphasize here that the implementation is a rather old one. 
     
    7775A direction for lateral mixing has to be defined when the desired operator does not act along the model levels. 
    7876This occurs when $(a)$ horizontal mixing is required on tracer or momentum 
    79 (\np{ln\_traldf\_hor} or \np{ln\_dynldf\_hor}) in $s$- or mixed $s$-$z$- coordinates, 
     77(\np{ln_traldf_hor}{ln\_traldf\_hor} or \np{ln_dynldf_hor}{ln\_dynldf\_hor}) in $s$- or mixed $s$-$z$- coordinates, 
    8078and $(b)$ isoneutral mixing is required whatever the vertical coordinate is. 
    8179This direction of mixing is defined by its slopes in the \textbf{i}- and \textbf{j}-directions at the face of 
    8280the cell of the quantity to be diffused. 
    8381For a tracer, this leads to the following four slopes: 
    84 $r_{1u}$, $r_{1w}$, $r_{2v}$, $r_{2w}$ (see \autoref{eq:tra_ldf_iso}), 
     82$r_{1u}$, $r_{1w}$, $r_{2v}$, $r_{2w}$ (see \autoref{eq:TRA_ldf_iso}), 
    8583while for momentum the slopes are  $r_{1t}$, $r_{1uw}$, $r_{2f}$, $r_{2uw}$ for $u$ and 
    86 $r_{1f}$, $r_{1vw}$, $r_{2t}$, $r_{2vw}$ for $v$.  
     84$r_{1f}$, $r_{1vw}$, $r_{2t}$, $r_{2vw}$ for $v$. 
    8785 
    8886%gm% add here afigure of the slope in i-direction 
    8987 
     88%% ================================================================================================= 
    9089\subsection{Slopes for tracer geopotential mixing in the $s$-coordinate} 
    9190 
    9291In $s$-coordinates, geopotential mixing (\ie\ horizontal mixing) $r_1$ and $r_2$ are the slopes between 
    9392the geopotential and computational surfaces. 
    94 Their discrete formulation is found by locally solving \autoref{eq:tra_ldf_iso} when 
     93Their discrete formulation is found by locally solving \autoref{eq:TRA_ldf_iso} when 
    9594the diffusive fluxes in the three directions are set to zero and $T$ is assumed to be horizontally uniform, 
    96 \ie\ a linear function of $z_T$, the depth of a $T$-point.  
     95\ie\ a linear function of $z_T$, the depth of a $T$-point. 
    9796%gm { Steven : My version is obviously wrong since I'm left with an arbitrary constant which is the local vertical temperature gradient} 
    9897 
    9998\begin{equation} 
    100   \label{eq:ldfslp_geo} 
     99  \label{eq:LDF_slp_geo} 
    101100  \begin{aligned} 
    102101    r_{1u} &= \frac{e_{3u}}{ \left( e_{1u}\;\overline{\overline{e_{3w}}}^{\,i+1/2,\,k} \right)} 
     
    113112\end{equation} 
    114113 
    115 %gm%  caution I'm not sure the simplification was a good idea!  
    116  
    117 These slopes are computed once in \rou{ldf\_slp\_init} when \np{ln\_sco}\forcode{ = .true.}, 
    118 and either \np{ln\_traldf\_hor}\forcode{ = .true.} or \np{ln\_dynldf\_hor}\forcode{ = .true.}.  
    119  
     114%gm%  caution I'm not sure the simplification was a good idea! 
     115 
     116These slopes are computed once in \rou{ldf\_slp\_init} when \np[=.true.]{ln_sco}{ln\_sco}, 
     117and either \np[=.true.]{ln_traldf_hor}{ln\_traldf\_hor} or \np[=.true.]{ln_dynldf_hor}{ln\_dynldf\_hor}. 
     118 
     119%% ================================================================================================= 
    120120\subsection{Slopes for tracer iso-neutral mixing} 
    121121\label{subsec:LDF_slp_iso} 
     
    125125Their discrete formulation is found using the fact that the diffusive fluxes of 
    126126locally 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 in 
     127So, substituting $T$ by $\rho$ in \autoref{eq:TRA_ldf_iso} and setting the diffusive fluxes in 
    128128the three directions to zero leads to the following definition for the neutral slopes: 
    129129 
    130130\begin{equation} 
    131   \label{eq:ldfslp_iso} 
     131  \label{eq:LDF_slp_iso} 
    132132  \begin{split} 
    133133    r_{1u} &= \frac{e_{3u}}{e_{1u}}\; \frac{\delta_{i+1/2}[\rho]} 
     
    145145 
    146146%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 to 
     147%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 
     153As the mixing is performed along neutral surfaces, the gradient of $\rho$ in \autoref{eq:LDF_slp_iso} has to 
    154154be evaluated at the same local pressure 
    155155(which, in decibars, is approximated by the depth in meters in the model). 
    156 Therefore \autoref{eq:ldfslp_iso} cannot be used as such, 
     156Therefore \autoref{eq:LDF_slp_iso} cannot be used as such, 
    157157but further transformation is needed depending on the vertical coordinate used: 
    158158 
    159159\begin{description} 
    160  
    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, 
     160\item [$z$-coordinate with full step:] in \autoref{eq:LDF_slp_iso} the densities appearing in the $i$ and $j$ derivatives  are taken at the same depth, 
    163161  thus the $in situ$ density can be used. 
    164162  This is not the case for the vertical derivatives: $\delta_{k+1/2}[\rho]$ is replaced by $-\rho N^2/g$, 
    165163  where $N^2$ is the local Brunt-Vais\"{a}l\"{a} frequency evaluated following \citet{mcdougall_JPO87} 
    166   (see \autoref{subsec:TRA_bn2}).  
    167  
    168 \item[$z$-coordinate with partial step: ] 
    169   this case is identical to the full step case except that at partial step level, 
     164  (see \autoref{subsec:TRA_bn2}). 
     165\item [$z$-coordinate with partial step:] this case is identical to the full step case except that at partial step level, 
    170166  the \emph{horizontal} density gradient is evaluated as described in \autoref{sec:TRA_zpshde}. 
    171  
    172 \item[$s$- or hybrid $s$-$z$- coordinate: ] 
    173   in the current release of \NEMO, iso-neutral mixing is only employed for $s$-coordinates if 
    174   the Griffies scheme is used (\np{ln\_traldf\_triad}\forcode{ = .true.}; 
    175   see \autoref{apdx:triad}). 
     167\item [$s$- or hybrid $s$-$z$- coordinate:] in the current release of \NEMO, iso-neutral mixing is only employed for $s$-coordinates if 
     168  the Griffies scheme is used (\np[=.true.]{ln_traldf_triad}{ln\_traldf\_triad}; 
     169  see \autoref{apdx:TRIADS}). 
    176170  In other words, iso-neutral mixing will only be accurately represented with a linear equation of state 
    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} 
     171  (\np[=.true.]{ln_seos}{ln\_seos}). 
     172  In the case of a "true" equation of state, the evaluation of $i$ and $j$ derivatives in \autoref{eq:LDF_slp_iso} 
    179173  will include a pressure dependent part, leading to the wrong evaluation of the neutral slopes. 
    180174 
    181 %gm%  
     175%gm% 
    182176  Note: The solution for $s$-coordinate passes trough the use of different (and better) expression for 
    183177  the constraint on iso-neutral fluxes. 
     
    193187 
    194188\[ 
    195   % \label{eq:ldfslp_iso2} 
     189  % \label{eq:LDF_slp_iso2} 
    196190  \begin{split} 
    197191    r_{1u} &= \frac{e_{3u}}{e_{1u}}\; \frac 
     
    221215 
    222216Note that such a formulation could be also used in the $z$-coordinate and $z$-coordinate with partial steps cases. 
    223  
    224217\end{description} 
    225218 
     
    230223To overcome this problem, several techniques have been proposed in which the numerical schemes of 
    231224the 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}. 
     225Griffies's scheme is now available in \NEMO\ if \np[=.true.]{ln_traldf_triad}{ln\_traldf\_triad}; see \autoref{apdx:TRIADS}. 
    233226Here, another strategy is presented \citep{lazar_phd97}: 
    234227a local filtering of the iso-neutral slopes (made on 9 grid-points) prevents the development of 
     
    240233 
    241234Nevertheless, this iso-neutral operator does not ensure that variance cannot increase, 
    242 contrary to the \citet{griffies.gnanadesikan.ea_JPO98} operator which has that property.  
    243  
    244 %>>>>>>>>>>>>>>>>>>>>>>>>>>>> 
     235contrary to the \citet{griffies.gnanadesikan.ea_JPO98} operator which has that property. 
     236 
    245237\begin{figure}[!ht] 
    246   \begin{center} 
    247     \includegraphics[width=\textwidth]{Fig_LDF_ZDF1} 
    248     \caption { 
    249       \protect\label{fig:LDF_ZDF1} 
    250       averaging procedure for isopycnal slope computation. 
    251     } 
    252   \end{center} 
     238  \centering 
     239  \includegraphics[width=0.66\textwidth]{LDF_ZDF1} 
     240  \caption{Averaging procedure for isopycnal slope computation} 
     241  \label{fig:LDF_ZDF1} 
    253242\end{figure} 
    254 %>>>>>>>>>>>>>>>>>>>>>>>>>>>> 
    255  
    256 %There are three additional questions about the slope calculation.  
    257 %First the expression for the rotation tensor has been obtain assuming the "small slope" approximation, so a bound has to be imposed on slopes.  
    258 %Second, numerical stability issues also require a bound on slopes.  
     243 
     244%There are three additional questions about the slope calculation. 
     245%First the expression for the rotation tensor has been obtain assuming the "small slope" approximation, so a bound has to be imposed on slopes. 
     246%Second, numerical stability issues also require a bound on slopes. 
    259247%Third, the question of boundary condition specified on slopes... 
    260248 
    261249%from griffies: chapter 13.1.... 
    262250 
    263  
    264  
    265 % In addition and also for numerical stability reasons \citep{cox_OM87, griffies_bk04},  
    266 % the slopes are bounded by $1/100$ everywhere. This limit is decreasing linearly  
    267 % to zero fom $70$ meters depth and the surface (the fact that the eddies "feel" the  
     251% In addition and also for numerical stability reasons \citep{cox_OM87, griffies_bk04}, 
     252% the slopes are bounded by $1/100$ everywhere. This limit is decreasing linearly 
     253% to zero fom $70$ meters depth and the surface (the fact that the eddies "feel" the 
    268254% surface motivates this flattening of isopycnals near the surface). 
    269255 
    270256For numerical stability reasons \citep{cox_OM87, griffies_bk04}, the slopes must also be bounded by 
    271 the namelist scalar \np{rn\_slpmax} (usually $1/100$) everywhere. 
     257the namelist scalar \np{rn_slpmax}{rn\_slpmax} (usually $1/100$) everywhere. 
    272258This constraint is applied in a piecewise linear fashion, increasing from zero at the surface to 
    273259$1/100$ at $70$ metres and thereafter decreasing to zero at the bottom of the ocean 
     
    275261\colorbox{yellow}{The way slopes are tapered has be checked. Not sure that this is still what is actually done.} 
    276262 
    277 %>>>>>>>>>>>>>>>>>>>>>>>>>>>> 
    278263\begin{figure}[!ht] 
    279   \begin{center} 
    280     \includegraphics[width=\textwidth]{Fig_eiv_slp} 
    281     \caption{ 
    282       \protect\label{fig:eiv_slp} 
    283       Vertical profile of the slope used for lateral mixing in the mixed layer: 
    284       \textit{(a)} in the real ocean the slope is the iso-neutral slope in the ocean interior, 
    285       which has to be adjusted at the surface boundary 
    286       \ie\ it must tend to zero at the surface since there is no mixing across the air-sea interface: 
    287       wall boundary condition). 
    288       Nevertheless, the profile between the surface zero value and the interior iso-neutral one is unknown, 
    289       and especially the value at the base of the mixed layer; 
    290       \textit{(b)} profile of slope using a linear tapering of the slope near the surface and 
    291       imposing a maximum slope of 1/100; 
    292       \textit{(c)} profile of slope actually used in \NEMO: a linear decrease of the slope from 
    293       zero at the surface to its ocean interior value computed just below the mixed layer. 
    294       Note the huge change in the slope at the base of the mixed layer between \textit{(b)} and \textit{(c)}. 
    295     } 
    296   \end{center} 
     264  \centering 
     265  \includegraphics[width=0.66\textwidth]{LDF_eiv_slp} 
     266  \caption[Vertical profile of the slope used for lateral mixing in the mixed layer]{ 
     267    Vertical profile of the slope used for lateral mixing in the mixed layer: 
     268    \textit{(a)} in the real ocean the slope is the iso-neutral slope in the ocean interior, 
     269    which has to be adjusted at the surface boundary 
     270    \ie\ it must tend to zero at the surface since there is no mixing across the air-sea interface: 
     271    wall boundary condition). 
     272    Nevertheless, 
     273    the profile between the surface zero value and the interior iso-neutral one is unknown, 
     274    and especially the value at the base of the mixed layer; 
     275    \textit{(b)} profile of slope using a linear tapering of the slope near the surface and 
     276    imposing a maximum slope of 1/100; 
     277    \textit{(c)} profile of slope actually used in \NEMO: 
     278    a linear decrease of the slope from zero at the surface to 
     279    its ocean interior value computed just below the mixed layer. 
     280    Note the huge change in the slope at the base of the mixed layer between 
     281    \textit{(b)} and \textit{(c)}.} 
     282  \label{fig:LDF_eiv_slp} 
    297283\end{figure} 
    298 %>>>>>>>>>>>>>>>>>>>>>>>>>>>> 
    299284 
    300285\colorbox{yellow}{add here a discussion about the flattening of the slopes, vs tapering the coefficient.} 
    301286 
     287%% ================================================================================================= 
    302288\subsection{Slopes for momentum iso-neutral mixing} 
    303289 
    304290The iso-neutral diffusion operator on momentum is the same as the one used on tracers but 
    305291applied to each component of the velocity separately 
    306 (see \autoref{eq:dyn_ldf_iso} in section~\autoref{subsec:DYN_ldf_iso}). 
     292(see \autoref{eq:DYN_ldf_iso} in section~\autoref{subsec:DYN_ldf_iso}). 
    307293The slopes between the surface along which the diffusion operator acts and the surface of computation 
    308294($z$- or $s$-surfaces) are defined at $T$-, $f$-, and \textit{uw}- points for the $u$-component, and $T$-, $f$- and 
    309295\textit{vw}- points for the $v$-component. 
    310296They are computed from the slopes used for tracer diffusion, 
    311 \ie\ \autoref{eq:ldfslp_geo} and \autoref{eq:ldfslp_iso}: 
     297\ie\ \autoref{eq:LDF_slp_geo} and \autoref{eq:LDF_slp_iso}: 
    312298 
    313299\[ 
    314   % \label{eq:ldfslp_dyn} 
     300  % \label{eq:LDF_slp_dyn} 
    315301  \begin{aligned} 
    316302    &r_{1t}\ \ = \overline{r_{1u}}^{\,i}       &&&    r_{1f}\ \ &= \overline{r_{1u}}^{\,i+1/2} \\ 
     
    326312(see \autoref{sec:LBC_coast}). 
    327313 
    328     
    329 % ================================================================ 
    330 % Lateral Mixing Coefficients 
    331 % ================================================================ 
    332 \section[Lateral mixing coefficient (\forcode{nn_aht_ijk_t}, \forcode{nn_ahm_ijk_t})] 
    333 {Lateral mixing coefficient (\protect\np{nn\_aht\_ijk\_t}, \protect\np{nn\_ahm\_ijk\_t})} 
     314%% ================================================================================================= 
     315\section[Lateral mixing coefficient (\forcode{nn_aht_ijk_t} \& \forcode{nn_ahm_ijk_t})]{Lateral mixing coefficient (\protect\np{nn_aht_ijk_t}{nn\_aht\_ijk\_t} \& \protect\np{nn_ahm_ijk_t}{nn\_ahm\_ijk\_t})} 
    334316\label{sec:LDF_coef} 
    335317 
    336 The specification of the space variation of the coefficient is made in modules \mdl{ldftra} and \mdl{ldfdyn}.  
     318The specification of the space variation of the coefficient is made in modules \mdl{ldftra} and \mdl{ldfdyn}. 
    337319The way the mixing coefficients are set in the reference version can be described as follows: 
    338320 
    339 \subsection[Mixing coefficients read from file (\forcode{nn_aht_ijk_t = -20, -30}, \forcode{nn_ahm_ijk_t = -20,-30})] 
    340 { Mixing coefficients read from file (\protect\np{nn\_aht\_ijk\_t}\forcode{ = -20, -30}, \protect\np{nn\_ahm\_ijk\_t}\forcode{ = -20, -30})} 
    341  
    342 Mixing coefficients can be read from file if a particular geographical variation is needed. For example, in the ORCA2 global ocean model,  
     321%% ================================================================================================= 
     322\subsection[Mixing coefficients read from file (\forcode{=-20, -30})]{ Mixing coefficients read from file (\protect\np[=-20, -30]{nn_aht_ijk_t}{nn\_aht\_ijk\_t} \& \protect\np[=-20, -30]{nn_ahm_ijk_t}{nn\_ahm\_ijk\_t})} 
     323 
     324Mixing coefficients can be read from file if a particular geographical variation is needed. For example, in the ORCA2 global ocean model, 
    343325the laplacian viscosity operator uses $A^l$~= 4.10$^4$ m$^2$/s poleward of 20$^{\circ}$ north and south and 
    344 decreases linearly to $A^l$~= 2.10$^3$ m$^2$/s at the equator \citep{madec.delecluse.ea_JPO96, delecluse.madec_icol99}.  
    345 Similar modified horizontal variations can be found with the Antarctic or Arctic sub-domain options of ORCA2 and ORCA05.  
    346 The provided fields can either be 2d (\np{nn\_aht\_ijk\_t}\forcode{ = -20}, \np{nn\_ahm\_ijk\_t}\forcode{ = -20}) or 3d (\np{nn\_aht\_ijk\_t}\forcode{ = -30},  \np{nn\_ahm\_ijk\_t}\forcode{ = -30}). They must be given at U, V points for tracers and T, F points for momentum (see \autoref{tab:LDF_files}). 
    347  
    348 %-------------------------------------------------TABLE--------------------------------------------------- 
     326decreases linearly to $A^l$~= 2.10$^3$ m$^2$/s at the equator \citep{madec.delecluse.ea_JPO96, delecluse.madec_icol99}. 
     327Similar modified horizontal variations can be found with the Antarctic or Arctic sub-domain options of ORCA2 and ORCA05. 
     328The provided fields can either be 2d (\np[=-20]{nn_aht_ijk_t}{nn\_aht\_ijk\_t}, \np[=-20]{nn_ahm_ijk_t}{nn\_ahm\_ijk\_t}) or 3d (\np[=-30]{nn_aht_ijk_t}{nn\_aht\_ijk\_t},  \np[=-30]{nn_ahm_ijk_t}{nn\_ahm\_ijk\_t}). They must be given at U, V points for tracers and T, F points for momentum (see \autoref{tab:LDF_files}). 
     329 
    349330\begin{table}[htb] 
    350   \begin{center} 
    351     \begin{tabular}{|l|l|l|l|} 
    352       \hline 
    353       Namelist parameter                        & Input filename                               & dimensions & variable names                      \\  \hline 
    354       \np{nn\_ahm\_ijk\_t}\forcode{ = -20}       & \forcode{eddy_viscosity_2D.nc }            &     $(i,j)$         & \forcode{ahmt_2d, ahmf_2d}  \\  \hline 
    355       \np{nn\_aht\_ijk\_t}\forcode{ = -20}           & \forcode{eddy_diffusivity_2D.nc }           &     $(i,j)$          & \forcode{ahtu_2d, ahtv_2d}    \\   \hline 
    356       \np{nn\_ahm\_ijk\_t}\forcode{ = -30}       & \forcode{eddy_viscosity_3D.nc }            &     $(i,j,k)$          & \forcode{ahmt_3d, ahmf_3d}  \\  \hline 
    357       \np{nn\_aht\_ijk\_t}\forcode{ = -30}       & \forcode{eddy_diffusivity_3D.nc }           &     $(i,j,k)$         & \forcode{ahtu_3d, ahtv_3d}    \\   \hline 
    358     \end{tabular} 
    359     \caption{ 
    360       \protect\label{tab:LDF_files} 
    361       Description of expected input files if mixing coefficients are read from NetCDF files. 
    362     } 
    363   \end{center} 
     331  \centering 
     332  \begin{tabular}{|l|l|l|l|} 
     333    \hline 
     334    Namelist parameter                       & Input filename                               & dimensions & variable names                      \\  \hline 
     335    \np[=-20]{nn_ahm_ijk_t}{nn\_ahm\_ijk\_t}     & \forcode{eddy_viscosity_2D.nc }            &     $(i,j)$         & \forcode{ahmt_2d, ahmf_2d}  \\  \hline 
     336    \np[=-20]{nn_aht_ijk_t}{nn\_aht\_ijk\_t}           & \forcode{eddy_diffusivity_2D.nc }           &     $(i,j)$           & \forcode{ahtu_2d, ahtv_2d}    \\   \hline 
     337    \np[=-30]{nn_ahm_ijk_t}{nn\_ahm\_ijk\_t}        & \forcode{eddy_viscosity_3D.nc }            &     $(i,j,k)$          & \forcode{ahmt_3d, ahmf_3d}  \\  \hline 
     338    \np[=-30]{nn_aht_ijk_t}{nn\_aht\_ijk\_t}     & \forcode{eddy_diffusivity_3D.nc }           &     $(i,j,k)$         & \forcode{ahtu_3d, ahtv_3d}    \\   \hline 
     339  \end{tabular} 
     340  \caption{Description of expected input files if mixing coefficients are read from NetCDF files} 
     341  \label{tab:LDF_files} 
    364342\end{table} 
    365 %-------------------------------------------------------------------------------------------------------------- 
    366  
    367 \subsection[Constant mixing coefficients (\forcode{nn_aht_ijk_t = 0}, \forcode{nn_ahm_ijk_t = 0})] 
    368 { Constant mixing coefficients (\protect\np{nn\_aht\_ijk\_t}\forcode{ = 0}, \protect\np{nn\_ahm\_ijk\_t}\forcode{ = 0})} 
     343 
     344%% ================================================================================================= 
     345\subsection[Constant mixing coefficients (\forcode{=0})]{ Constant mixing coefficients (\protect\np[=0]{nn_aht_ijk_t}{nn\_aht\_ijk\_t} \& \protect\np[=0]{nn_ahm_ijk_t}{nn\_ahm\_ijk\_t})} 
    369346 
    370347If constant, mixing coefficients are set thanks to a velocity and a length scales ($U_{scl}$, $L_{scl}$) such that: 
    371348 
    372349\begin{equation} 
    373   \label{eq:constantah} 
     350  \label{eq:LDF_constantah} 
    374351  A_o^l = \left\{ 
    375352    \begin{aligned} 
     
    380357\end{equation} 
    381358 
    382  $U_{scl}$ and $L_{scl}$ are given by the namelist parameters \np{rn\_Ud}, \np{rn\_Uv}, \np{rn\_Ld} and \np{rn\_Lv}. 
    383  
    384 \subsection[Vertically varying mixing coefficients (\forcode{nn_aht_ijk_t = 10}, \forcode{nn_ahm_ijk_t = 10})] 
    385 {Vertically varying mixing coefficients (\protect\np{nn\_aht\_ijk\_t}\forcode{ = 10}, \protect\np{nn\_ahm\_ijk\_t}\forcode{ = 10})} 
     359 $U_{scl}$ and $L_{scl}$ are given by the namelist parameters \np{rn_Ud}{rn\_Ud}, \np{rn_Uv}{rn\_Uv}, \np{rn_Ld}{rn\_Ld} and \np{rn_Lv}{rn\_Lv}. 
     360 
     361%% ================================================================================================= 
     362\subsection[Vertically varying mixing coefficients (\forcode{=10})]{Vertically varying mixing coefficients (\protect\np[=10]{nn_aht_ijk_t}{nn\_aht\_ijk\_t} \& \protect\np[=10]{nn_ahm_ijk_t}{nn\_ahm\_ijk\_t})} 
    386363 
    387364In 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, 
     365the surface value is given by \autoref{eq:LDF_constantah}, the bottom value is 1/4 of the surface value, 
    389366and the transition takes place around z=500~m with a width of 200~m. 
    390367This profile is hard coded in module \mdl{ldfc1d\_c2d}, but can be easily modified by users. 
    391368 
    392 \subsection[Mesh size dependent mixing coefficients (\forcode{nn_aht_ijk_t = 20}, \forcode{nn_ahm_ijk_t = 20})] 
    393 {Mesh size dependent mixing coefficients (\protect\np{nn\_aht\_ijk\_t}\forcode{ = 20}, \protect\np{nn\_ahm\_ijk\_t}\forcode{ = 20})} 
     369%% ================================================================================================= 
     370\subsection[Mesh size dependent mixing coefficients (\forcode{=20})]{Mesh size dependent mixing coefficients (\protect\np[=20]{nn_aht_ijk_t}{nn\_aht\_ijk\_t} \& \protect\np[=20]{nn_ahm_ijk_t}{nn\_ahm\_ijk\_t})} 
    394371 
    395372In that case, the horizontal variation of the eddy coefficient depends on the local mesh size and 
    396373the type of operator used: 
    397374\begin{equation} 
    398   \label{eq:title} 
     375  \label{eq:LDF_title} 
    399376  A_l = \left\{ 
    400377    \begin{aligned} 
     
    404381  \right. 
    405382\end{equation} 
    406 where $U_{scl}$ is a user defined velocity scale (\np{rn\_Ud}, \np{rn\_Uv}). 
     383where $U_{scl}$ is a user defined velocity scale (\np{rn_Ud}{rn\_Ud}, \np{rn_Uv}{rn\_Uv}). 
    407384This variation is intended to reflect the lesser need for subgrid scale eddy mixing where 
    408385the grid size is smaller in the domain. 
     
    411388model configurations presenting large changes in grid spacing such as global ocean models. 
    412389Indeed, 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}), 
     390large coefficient compare to the smallest grid size (see \autoref{sec:TD_forward_imp}), 
    414391especially when using a bilaplacian operator. 
    415392 
    416 \colorbox{yellow}{CASE \np{nn\_aht\_ijk\_t} = 21 to be added} 
    417  
    418 \subsection[Mesh size and depth dependent mixing coefficients (\forcode{nn_aht_ijk_t = 30}, \forcode{nn_ahm_ijk_t = 30})] 
    419 {Mesh size and depth dependent mixing coefficients (\protect\np{nn\_aht\_ijk\_t}\forcode{ = 30}, \protect\np{nn\_ahm\_ijk\_t}\forcode{ = 30})} 
     393\colorbox{yellow}{CASE \np{nn_aht_ijk_t}{nn\_aht\_ijk\_t} = 21 to be added} 
     394 
     395%% ================================================================================================= 
     396\subsection[Mesh size and depth dependent mixing coefficients (\forcode{=30})]{Mesh size and depth dependent mixing coefficients (\protect\np[=30]{nn_aht_ijk_t}{nn\_aht\_ijk\_t} \& \protect\np[=30]{nn_ahm_ijk_t}{nn\_ahm\_ijk\_t})} 
    420397 
    421398The 3D space variation of the mixing coefficient is simply the combination of the 1D and 2D cases above, 
    422399\ie\ a hyperbolic tangent variation with depth associated with a grid size dependence of 
    423 the magnitude of the coefficient.  
    424  
    425 \subsection[Velocity dependent mixing coefficients (\forcode{nn_aht_ijk_t = 31}, \forcode{nn_ahm_ijk_t = 31})] 
    426 {Flow dependent mixing coefficients (\protect\np{nn\_aht\_ijk\_t}\forcode{ = 31}, \protect\np{nn\_ahm\_ijk\_t}\forcode{ = 31})} 
     400the magnitude of the coefficient. 
     401 
     402%% ================================================================================================= 
     403\subsection[Velocity dependent mixing coefficients (\forcode{=31})]{Flow dependent mixing coefficients (\protect\np[=31]{nn_aht_ijk_t}{nn\_aht\_ijk\_t} \& \protect\np[=31]{nn_ahm_ijk_t}{nn\_ahm\_ijk\_t})} 
    427404In that case, the eddy coefficient is proportional to the local velocity magnitude so that the Reynolds number $Re =  \lvert U \rvert  e / A_l$ is constant (and here hardcoded to $12$): 
    428405\colorbox{yellow}{JC comment: The Reynolds is effectively set to 12 in the code for both operators but shouldn't it be 2 for Laplacian ?} 
    429406 
    430407\begin{equation} 
    431   \label{eq:flowah} 
     408  \label{eq:LDF_flowah} 
    432409  A_l = \left\{ 
    433410    \begin{aligned} 
    434411      & \frac{1}{12} \lvert U \rvert e          & \text{for laplacian operator } \\ 
    435       & \frac{1}{12} \lvert U \rvert e^3             & \text{for bilaplacian operator }  
     412      & \frac{1}{12} \lvert U \rvert e^3             & \text{for bilaplacian operator } 
    436413    \end{aligned} 
    437414  \right. 
    438415\end{equation} 
    439416 
    440 \subsection[Deformation rate dependent viscosities (\forcode{nn_ahm_ijk_t = 32})] 
    441 {Deformation rate dependent viscosities (\protect\np{nn\_ahm\_ijk\_t}\forcode{ = 32})} 
    442  
    443 This option refers to the \citep{smagorinsky_MW63} scheme which is here implemented for momentum only. Smagorinsky chose as a  
     417%% ================================================================================================= 
     418\subsection[Deformation rate dependent viscosities (\forcode{nn_ahm_ijk_t=32})]{Deformation rate dependent viscosities (\protect\np[=32]{nn_ahm_ijk_t}{nn\_ahm\_ijk\_t})} 
     419 
     420This option refers to the \citep{smagorinsky_MW63} scheme which is here implemented for momentum only. Smagorinsky chose as a 
    444421characteristic time scale $T_{smag}$ the deformation rate and for the lengthscale $L_{smag}$ the maximum wavenumber possible on the horizontal grid, e.g.: 
    445422 
    446423\begin{equation} 
    447   \label{eq:smag1} 
     424  \label{eq:LDF_smag1} 
    448425  \begin{split} 
    449426    T_{smag}^{-1} & = \sqrt{\left( \partial_x u - \partial_y v\right)^2 + \left( \partial_y u + \partial_x v\right)^2  } \\ 
     
    452429\end{equation} 
    453430 
    454 Introducing a user defined constant $C$ (given in the namelist as \np{rn\_csmc}), one can deduce the mixing coefficients as follows: 
    455  
    456 \begin{equation} 
    457   \label{eq:smag2} 
     431Introducing a user defined constant $C$ (given in the namelist as \np{rn_csmc}{rn\_csmc}), one can deduce the mixing coefficients as follows: 
     432 
     433\begin{equation} 
     434  \label{eq:LDF_smag2} 
    458435  A_{smag} = \left\{ 
    459436    \begin{aligned} 
    460437      & C^2  T_{smag}^{-1}  L_{smag}^2       & \text{for laplacian operator } \\ 
    461       & \frac{C^2}{8} T_{smag}^{-1} L_{smag}^4        & \text{for bilaplacian operator }  
     438      & \frac{C^2}{8} T_{smag}^{-1} L_{smag}^4        & \text{for bilaplacian operator } 
    462439    \end{aligned} 
    463440  \right. 
    464441\end{equation} 
    465442 
    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} 
     443For stability reasons, upper and lower limits are applied on the resulting coefficient (see \autoref{sec:TD_forward_imp}) so that: 
     444\begin{equation} 
     445  \label{eq:LDF_smag3} 
    469446    \begin{aligned} 
    470447      & C_{min} \frac{1}{2}   \lvert U \rvert  e    < A_{smag} < C_{max} \frac{e^2}{   8\rdt}                 & \text{for laplacian operator } \\ 
    471       & C_{min} \frac{1}{12} \lvert U \rvert  e^3 < A_{smag} < C_{max} \frac{e^4}{64 \rdt}                 & \text{for bilaplacian operator }  
     448      & C_{min} \frac{1}{12} \lvert U \rvert  e^3 < A_{smag} < C_{max} \frac{e^4}{64 \rdt}                 & \text{for bilaplacian operator } 
    472449    \end{aligned} 
    473450\end{equation} 
    474451 
    475 where $C_{min}$ and $C_{max}$ are adimensional namelist parameters given by \np{rn\_minfac} and \np{rn\_maxfac} respectively. 
    476  
     452where $C_{min}$ and $C_{max}$ are adimensional namelist parameters given by \np{rn_minfac}{rn\_minfac} and \np{rn_maxfac}{rn\_maxfac} respectively. 
     453 
     454%% ================================================================================================= 
    477455\subsection{About space and time varying mixing coefficients} 
    478456 
     
    480458 
    481459(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}). 
     460divergent components of the horizontal current (see \autoref{subsec:MB_ldf}). 
    483461Although the eddy coefficient could be set to different values in these two terms, 
    484 this option is not currently available.  
     462this option is not currently available. 
    485463 
    486464(2) with an horizontally varying viscosity, the quadratic integral constraints on enstrophy and on the square of 
    487465the horizontal divergence for operators acting along model-surfaces are no longer satisfied 
    488 (\autoref{sec:dynldf_properties}). 
    489  
    490 % ================================================================ 
    491 % Eddy Induced Mixing 
    492 % ================================================================ 
    493 \section[Eddy induced velocity (\forcode{ln_ldfeiv = .true.})] 
    494 {Eddy induced velocity (\protect\np{ln\_ldfeiv}\forcode{ = .true.})} 
     466(\autoref{sec:INVARIANTS_dynldf_properties}). 
     467 
     468%% ================================================================================================= 
     469\section[Eddy induced velocity (\forcode{ln_ldfeiv})]{Eddy induced velocity (\protect\np{ln_ldfeiv}{ln\_ldfeiv})} 
    495470 
    496471\label{sec:LDF_eiv} 
    497472 
    498 %--------------------------------------------namtra_eiv--------------------------------------------------- 
    499  
    500 \nlst{namtra_eiv} 
    501  
    502 %-------------------------------------------------------------------------------------------------------------- 
    503  
     473\begin{listing} 
     474  \nlst{namtra_eiv} 
     475  \caption{\forcode{&namtra_eiv}} 
     476  \label{lst:namtra_eiv} 
     477\end{listing} 
    504478 
    505479%%gm  from Triad appendix  : to be incorporated.... 
     
    507481  Values of iso-neutral diffusivity and GM coefficient are set as described in \autoref{sec:LDF_coef}. 
    508482  If none of the keys \key{traldf\_cNd}, N=1,2,3 is set (the default), spatially constant iso-neutral $A_l$ and 
    509   GM diffusivity $A_e$ are directly set by \np{rn\_aeih\_0} and \np{rn\_aeiv\_0}. 
     483  GM diffusivity $A_e$ are directly set by \np{rn_aeih_0}{rn\_aeih\_0} and \np{rn_aeiv_0}{rn\_aeiv\_0}. 
    510484  If 2D-varying coefficients are set with \key{traldf\_c2d} then $A_l$ is reduced in proportion with horizontal 
    511485  scale factor according to \autoref{eq:title} 
     
    520494    In this case, $A_e$ at low latitudes $|\theta|<20^{\circ}$ is further reduced by a factor $|f/f_{20}|$, 
    521495    where $f_{20}$ is the value of $f$ at $20^{\circ}$~N 
    522   } (\mdl{ldfeiv}) and \np{rn\_aeiv\_0} is ignored unless it is zero. 
     496  } (\mdl{ldfeiv}) and \np{rn_aeiv_0}{rn\_aeiv\_0} is ignored unless it is zero. 
    523497} 
    524498 
    525 When  \citet{gent.mcwilliams_JPO90} diffusion is used (\np{ln\_ldfeiv}\forcode{ = .true.}), 
     499When  \citet{gent.mcwilliams_JPO90} diffusion is used (\np[=.true.]{ln_ldfeiv}{ln\_ldfeiv}), 
    526500an eddy induced tracer advection term is added, 
    527501the formulation of which depends on the slopes of iso-neutral surfaces. 
    528502Contrary 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. 
    531  
    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 \begin{equation} 
    534   \label{eq:ldfeiv} 
     503\ie\ \autoref{eq:LDF_slp_geo} is used in $z$-coordinates, 
     504and the sum \autoref{eq:LDF_slp_geo} + \autoref{eq:LDF_slp_iso} in $s$-coordinates. 
     505 
     506If isopycnal mixing is used in the standard way, \ie\ \np[=.false.]{ln_traldf_triad}{ln\_traldf\_triad}, the eddy induced velocity is given by: 
     507\begin{equation} 
     508  \label{eq:LDF_eiv} 
    535509  \begin{split} 
    536510    u^* & = \frac{1}{e_{2u}e_{3u}}\; \delta_k \left[e_{2u} \, A_{uw}^{eiv} \; \overline{r_{1w}}^{\,i+1/2} \right]\\ 
     
    539513  \end{split} 
    540514\end{equation} 
    541 where $A^{eiv}$ is the eddy induced velocity coefficient whose value is set through \np{nn\_aei\_ijk\_t} \nam{tra\_eiv} namelist parameter.  
     515where $A^{eiv}$ is the eddy induced velocity coefficient whose value is set through \np{nn_aei_ijk_t}{nn\_aei\_ijk\_t} \nam{tra_eiv}{tra\_eiv} namelist parameter. 
    542516The three components of the eddy induced velocity are computed in \rou{ldf\_eiv\_trp} and 
    543517added to the eulerian velocity in \rou{tra\_adv} where tracer advection is performed. 
     
    547521previous releases of OPA \citep{madec.delecluse.ea_NPM98}. 
    548522This is particularly useful for passive tracers where \emph{positivity} of the advection scheme is of 
    549 paramount importance.  
     523paramount importance. 
    550524 
    551525At the surface, lateral and bottom boundaries, the eddy induced velocity, 
    552 and thus the advective eddy fluxes of heat and salt, are set to zero.  
    553 The value of the eddy induced mixing coefficient and its space variation is controlled in a similar way as for lateral mixing coefficient described in the preceding subsection (\np{nn\_aei\_ijk\_t}, \np{rn\_Ue}, \np{rn\_Le} namelist parameters).  
    554 \colorbox{yellow}{CASE \np{nn\_aei\_ijk\_t} = 21 to be added} 
    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}. 
    557  
    558 % ================================================================ 
    559 % Mixed layer eddies 
    560 % ================================================================ 
    561 \section[Mixed layer eddies (\forcode{ln_mle = .true.})] 
    562 {Mixed layer eddies (\protect\np{ln\_mle}\forcode{ = .true.})} 
    563  
     526and thus the advective eddy fluxes of heat and salt, are set to zero. 
     527The value of the eddy induced mixing coefficient and its space variation is controlled in a similar way as for lateral mixing coefficient described in the preceding subsection (\np{nn_aei_ijk_t}{nn\_aei\_ijk\_t}, \np{rn_Ue}{rn\_Ue}, \np{rn_Le}{rn\_Le} namelist parameters). 
     528\colorbox{yellow}{CASE \np{nn_aei_ijk_t}{nn\_aei\_ijk\_t} = 21 to be added} 
     529 
     530In case of setting \np[=.true.]{ln_traldf_triad}{ln\_traldf\_triad}, a skew form of the eddy induced advective fluxes is used, which is described in \autoref{apdx:TRIADS}. 
     531 
     532%% ================================================================================================= 
     533\section[Mixed layer eddies (\forcode{ln_mle})]{Mixed layer eddies (\protect\np{ln_mle}{ln\_mle})} 
    564534\label{sec:LDF_mle} 
    565535 
    566 %--------------------------------------------namtra_eiv--------------------------------------------------- 
    567  
    568 \nlst{namtra_mle} 
    569  
    570 %-------------------------------------------------------------------------------------------------------------- 
    571  
    572 If  \np{ln\_mle}\forcode{ = .true.} in \nam{tra\_mle} namelist, a parameterization of the mixing due to unresolved mixed layer instabilities is activated (\citet{foxkemper.ferrari_JPO08}). Additional transport is computed in \rou{ldf\_mle\_trp} and added to the eulerian transport in \rou{tra\_adv} as done for eddy induced advection. 
     536\begin{listing} 
     537  \nlst{namtra_mle} 
     538  \caption{\forcode{&namtra_mle}} 
     539  \label{lst:namtra_mle} 
     540\end{listing} 
     541 
     542If  \np[=.true.]{ln_mle}{ln\_mle} in \nam{tra_mle}{tra\_mle} namelist, a parameterization of the mixing due to unresolved mixed layer instabilities is activated (\citet{foxkemper.ferrari_JPO08}). Additional transport is computed in \rou{ldf\_mle\_trp} and added to the eulerian transport in \rou{tra\_adv} as done for eddy induced advection. 
    573543 
    574544\colorbox{yellow}{TBC} 
    575545 
    576 \biblio 
    577  
    578 \pindex 
     546\onlyinsubfile{\input{../../global/epilogue}} 
    579547 
    580548\end{document} 
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