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Changeset 10442 for NEMO/trunk/doc/latex/NEMO/subfiles/chap_LBC.tex – NEMO

Ignore:
Timestamp:
2018-12-21T15:18:38+01:00 (5 years ago)
Author:
nicolasmartin
Message:

Front page edition, cleaning in custom LaTeX commands and add index for single subfile compilation

  • Use \thanks storing cmd to refer to the ST members list for 2018 in an footnote on the cover page
  • NEMO and Fortran in small capitals
  • Removing of unused or underused custom cmds, move local cmds to their respective .tex file
  • Addition of new ones (\zstar, \ztilde, \sstar, \stilde, \ie, \eg, \fortran, \fninety)
  • Fonts for indexed items: italic font for files (modules and .nc files), preformat for code (CPP keys, routines names and namelists content)
File:
1 edited

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  • NEMO/trunk/doc/latex/NEMO/subfiles/chap_LBC.tex

    r10414 r10442  
    2626%The lateral ocean boundary conditions contiguous to coastlines are Neumann conditions for heat and salt (no flux across boundaries) and Dirichlet conditions for momentum (ranging from free-slip to "strong" no-slip). They are handled automatically by the mask system (see \autoref{subsec:DOM_msk}).  
    2727 
    28 %OPA allows land and topography grid points in the computational domain due to the presence of continents or islands, and includes the use of a full or partial step representation of bottom topography. The computation is performed over the whole domain, i.e. we do not try to restrict the computation to ocean-only points. This choice has two motivations. Firstly, working on ocean only grid points overloads the code and harms the code readability. Secondly, and more importantly, it drastically reduces the vector portion of the computation, leading to a dramatic increase of CPU time requirement on vector computers.  The current section describes how the masking affects the computation of the various terms of the equations with respect to the boundary condition at solid walls. The process of defining which areas are to be masked is described in \autoref{subsec:DOM_msk}. 
     28%OPA allows land and topography grid points in the computational domain due to the presence of continents or islands, and includes the use of a full or partial step representation of bottom topography. The computation is performed over the whole domain, \ie we do not try to restrict the computation to ocean-only points. This choice has two motivations. Firstly, working on ocean only grid points overloads the code and harms the code readability. Secondly, and more importantly, it drastically reduces the vector portion of the computation, leading to a dramatic increase of CPU time requirement on vector computers.  The current section describes how the masking affects the computation of the various terms of the equations with respect to the boundary condition at solid walls. The process of defining which areas are to be masked is described in \autoref{subsec:DOM_msk}. 
    2929 
    3030Options are defined through the \ngn{namlbc} namelist variables. 
    … …  
    4040Since most of the boundary conditions consist of a zero flux across the solid boundaries, 
    4141they can be simply applied by multiplying variables by the correct mask arrays, 
    42 $i.e.$ the mask array of the grid point where the flux is evaluated. 
     42\ie the mask array of the grid point where the flux is evaluated. 
    4343For example, the heat flux in the \textbf{i}-direction is evaluated at $u$-points. 
    4444Evaluating this quantity as, 
    … …  
    103103\item[free-slip boundary condition (\np{rn\_shlat}\forcode{ = 0}):] the tangential velocity at 
    104104  the coastline is equal to the offshore velocity, 
    105   $i.e.$ the normal derivative of the tangential velocity is zero at the coast, 
     105  \ie the normal derivative of the tangential velocity is zero at the coast, 
    106106  so the vorticity: mask$_{f}$ array is set to zero inside the land and just at the coast 
    107107  (\autoref{fig:LBC_shlat}-a). 
    … …  
    129129 
    130130\item["partial" free-slip boundary condition (0$<$\np{rn\_shlat}$<$2):] the tangential velocity at 
    131   the coastline is smaller than the offshore velocity, $i.e.$ there is a lateral friction but 
     131  the coastline is smaller than the offshore velocity, \ie there is a lateral friction but 
    132132  not strong enough to make the tangential velocity at the coast vanish (\autoref{fig:LBC_shlat}-c). 
    133133  This can be selected by providing a value of mask$_{f}$ strictly inbetween $0$ and $2$. 
    … …  
    165165Each time such a boundary condition is needed, it is set by a call to routine \mdl{lbclnk}. 
    166166The computation of momentum and tracer trends proceeds from $i=2$ to $i=jpi-1$ and from $j=2$ to $j=jpj-1$, 
    167 $i.e.$ in the model interior. 
     167\ie in the model interior. 
    168168To choose a lateral model boundary condition is to specify the first and last rows and columns of 
    169169the model variables.  
    … …  
    242242are organized by explicit statements (message passing method). 
    243243 
    244 A big advantage is that the method does not need many modifications of the initial FORTRAN code. 
     244A big advantage is that the method does not need many modifications of the initial \fortran code. 
    245245From the modeller's point of view, each sub domain running on a processor is identical to the "mono-domain" code. 
    246246In addition, the programmer manages the communications between subdomains, 
    … …  
    267267After a computation, a communication phase starts: 
    268268each processor sends to its neighbouring processors the update values of the points corresponding to 
    269 the interior overlapping area to its neighbouring sub-domain ($i.e.$ the innermost of the two overlapping rows). 
     269the interior overlapping area to its neighbouring sub-domain (\ie the innermost of the two overlapping rows). 
    270270The communication is done through the Message Passing Interface (MPI). 
    271271The data exchanges between processors are required at the very place where 
    272272lateral domain boundary conditions are set in the mono-domain computation: 
    273273the \rou{lbc\_lnk} routine (found in \mdl{lbclnk} module) which manages such conditions is interfaced with 
    274 routines found in \mdl{lib\_mpp} module when running on an MPP computer ($i.e.$ when \key{mpp\_mpi} defined). 
     274routines found in \mdl{lib\_mpp} module when running on an MPP computer (\ie when \key{mpp\_mpi} defined). 
    275275It has to be pointed out that when using the MPP version of the model, 
    276276the east-west cyclic boundary condition is done implicitly, 
    … …  
    355355Note that this is a problem for the meshmask file which requires to be defined over the whole domain. 
    356356Therefore, user should not eliminate land processors when creating a meshmask file 
    357 ($i.e.$ when setting a non-zero value to \np{nn\_msh}). 
     357(\ie when setting a non-zero value to \np{nn\_msh}). 
    358358 
    359359%>>>>>>>>>>>>>>>>>>>>>>>>>>>> 
    … …  
    518518Note that the sea-surface height gradient in \autoref{eq:bdy_fla1} is a spatial gradient across the model boundary, 
    519519so that $\eta_{e}$ is defined on the $T$ points with $nbr=1$ and $\eta$ is defined on the $T$ points with $nbr=2$. 
    520 $U$ and $U_{e}$ are defined on the $U$ or $V$ points with $nbr=1$, $i.e.$ between the two $T$ grid points. 
     520$U$ and $U_{e}$ are defined on the $U$ or $V$ points with $nbr=1$, \ie between the two $T$ grid points. 
    521521 
    522522%---------------------------------------------- 
    … …  
    594594 
    595595These restrictions mean that data files used with previous versions of the model may not work with version 3.4. 
    596 A fortran utility {\it bdy\_reorder} exists in the TOOLS directory which 
     596A\fortran utility {\it bdy\_reorder} exists in the TOOLS directory which 
    597597will re-order the data in old BDY data files.  
    598598 
    … …  
    641641\biblio 
    642642 
     643\pindex 
     644 
    643645\end{document} 
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