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Changeset 817 for trunk/DOC/BETA/Chapters/Chap_LDF.tex – NEMO

Ignore:
Timestamp:
2008-02-09T15:13:48+01:00 (16 years ago)
Author:
gm
Message:

trunk - update including Steven correction of the first 5 chapters (until DYN) and activation of Appendix A & B

File:
1 edited

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  • trunk/DOC/BETA/Chapters/Chap_LDF.tex

    r781 r817  
    2222% Lateral Mixing Coefficients 
    2323% ================================================================ 
    24 \section{Lateral Mixing Coefficient (key\_ldftra\_c.d and key\_ldfdyn\_c.d)} 
     24\section{Lateral Mixing Coefficient (\textbf{key\_ldftra\_c.d} - \textbf{key\_ldfdyn\_c.d)} } 
    2525\label{LDF_coef} 
    2626 
     
    6161\quad \text{comments} 
    6262\end{equation} 
    63 where $e_{max}$ is the max of $e_1$ and $e_2$ taken over the whole masked ocean domain, and $A_o^l$ is \np{ahm0} (momentum) or \np{aht0} (tracer) namelist parameters. This variation is intended to reflect the lesser need for subgrid scale eddy mixing where the grid size is smaller in the domain. It was introduced in the context of the DYNAMO modelling project \citep{Willebrand2001}. %gm  not only that! stability reasons: with non uniform grid size, it is common to face a blow up of the model due to to large diffusive coefficient compare to the smallest grid size... this is especially true for bilaplacian (to be added in the text!)   
    64  
    65 Other formulations can be introduced by the user for a given configuration. For example, in the ORCA2 global ocean model (\key{orca\_r2}), the laplacian viscous operator uses \np{ahm0}~=~$4.10^4 m^2.s^{-1}$ poleward of 20$^{\circ}$ north and south and decreases to \np{aht0}~=~$2.10^3 m^2.s^{-1}$ at the equator \citep{Madec1996, Delecluse2000}. This specification can be found in \rou{ldf\_dyn\_c2d\_orca} routine defined in \mdl{ldfdyn\_c2d}. Similar specific horizontal variation can be found for Antarctic or Arctic sub-domain of ORCA2 and ORCA05 (\key{antarctic} or \key{arctic} defined, see \hf{ldfdyn\_antarctic} and \hf{ldfdyn\_arctic}). 
     63where $e_{max}$ is the max of $e_1$ and $e_2$ taken over the whole masked ocean domain, and $A_o^l$ is \np{ahm0} (momentum) or \np{aht0} (tracer) namelist parameters. This variation is intended to reflect the lesser need for subgrid scale eddy mixing where the grid size is smaller in the domain. It was introduced in the context of the DYNAMO modelling project \citep{Willebrand2001}.  
     64%%% 
     65\gmcomment { not only that! stability reasons: with non uniform grid size, it is common to face a blow up of the model due to to large diffusive coefficient compare to the smallest grid size... this is especially true for bilaplacian (to be added in the text!)  } 
     66 
     67Other formulations can be introduced by the user for a given configuration. For example, in the ORCA2 global ocean model (\key{orca\_r2}), the laplacian viscous operator uses \np{ahm0}~=~$4.10^4 m^2.s^{-1}$ poleward of 20$^{\circ}$ north and south and decreases to \np{aht0}~=~$2.10^3 m^2.s^{-1}$ at the equator \citep{Madec1996, Delecluse_Madec_Bk00}. This specification can be found in \rou{ldf\_dyn\_c2d\_orca} routine defined in \mdl{ldfdyn\_c2d}. Similar specific horizontal variation can be found for Antarctic or Arctic sub-domain of ORCA2 and ORCA05 (\key{antarctic} or \key{arctic} defined, see \hf{ldfdyn\_antarctic} and \hf{ldfdyn\_arctic}). 
    6668 
    6769\subsubsection{Space Varying Mixing Coefficients (\key{ldftra\_c3d} and \key{ldfdyn\_c3d})} 
     
    9799% Direction of lateral Mixing 
    98100% ================================================================ 
    99 \section{Direction of Lateral Mixing (\mdl{ldfslp})} 
     101\section  [Direction of Lateral Mixing (\textit{ldfslp})] 
     102      {Direction of Lateral Mixing (\mdl{ldfslp})} 
    100103\label{LDF_slp} 
    101104 
    102 %gm%  we should emphasize here that the implementation is a rather old one. Better work can be achieved by using \citet{Griffies1998, Griffies2004} iso-neutral scheme. 
     105%%% 
     106\gmcomment{  we should emphasize here that the implementation is a rather old one. Better work can be achieved by using \citet{Griffies1998, Griffies2004} iso-neutral scheme. } 
    103107 
    104108 
     
    270274% Eddy Induced Mixing 
    271275% ================================================================ 
    272 \section{Eddy Induced Velocity (\mdl{traadv\_eiv}, \mdl{ldfeiv})} 
     276\section  [Eddy Induced Velocity (\textit{traadv\_eiv}, \textit{ldfeiv})] 
     277      {Eddy Induced Velocity (\mdl{traadv\_eiv}, \mdl{ldfeiv})} 
    273278\label{LDF_eiv} 
    274  
    275279 
    276280When Gent and McWilliams [1990] diffusion is used (\key{traldf\_eiv} defined), an eddy induced tracer advection term is added, the formulation of which depends on the slopes of iso-neutral surfaces. Contrary to iso-neutral mixing, the slopes use here are referenced to the geopotential surfaces, i.e. \eqref{Eq_ldfslp_geo} is used in $z$-coordinates, and the sum \eqref{Eq_ldfslp_geo}  + \eqref{Eq_ldfslp_iso} in $s$-coordinates. The eddy induced velocity is given by: 
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