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Changeset 9392 for branches/2017/dev_merge_2017/DOC/tex_sub/chap_time_domain.tex – NEMO

Ignore:
Timestamp:
2018-03-09T16:57:00+01:00 (6 years ago)
Author:
nicolasmartin
Message:

Global replacement of patterns \np{id}=value by \forcode{id = value} for integer and booleans

File:
1 edited

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  • branches/2017/dev_merge_2017/DOC/tex_sub/chap_time_domain.tex

    r9389 r9392  
    9191\end{equation}  
    9292where the subscript $F$ denotes filtered values and $\gamma$ is the Asselin  
    93 coefficient. $\gamma$ is initialized as \np{rn\_atfp} (namelist parameter).  
    94 Its default value is \np{rn\_atfp}=$10^{-3}$ (see \S~\ref{STP_mLF}),  
     93coefficient. $\gamma$ is initialized as \np{rn_atfp} (namelist parameter).  
     94Its default value is \np{rn_atfp}=$10^{-3}$ (see \S~\ref{STP_mLF}),  
    9595causing only a weak dissipation of high frequency motions (\citep{Farge1987}).  
    9696The addition of a time filter degrades the accuracy of the  
     
    141141constraint on the time step. Two solutions are available in \NEMO to overcome  
    142142the stability constraint: $(a)$ a forward time differencing scheme using a  
    143 time splitting technique (\np{ln\_zdfexp} = true) or $(b)$ a backward (or implicit)  
    144 time differencing scheme (\np{ln\_zdfexp} = false). In $(a)$, the master  
     143time splitting technique (\np{ln_zdfexp} = true) or $(b)$ a backward (or implicit)  
     144time differencing scheme (\np{ln_zdfexp} = false). In $(a)$, the master  
    145145time step $\Delta $t is cut into $N$ fractional time steps so that the  
    146146stability criterion is reduced by a factor of $N$. The computation is performed as  
     
    156156\end{equation} 
    157157with DF a vertical diffusion term. The number of fractional time steps, $N$, is given  
    158 by setting \np{nn\_zdfexp}, (namelist parameter). The scheme $(b)$ is unconditionally  
     158by setting \np{nn_zdfexp}, (namelist parameter). The scheme $(b)$ is unconditionally  
    159159stable but diffusive. It can be written as follows: 
    160160\begin{equation} \label{Eq_STP_imp} 
     
    309309gradient (see \S\ref{DYN_hpg_imp}), an extra three-dimensional field has to be  
    310310added to the restart file to ensure an exact restartability. This is done optionally  
    311 via the  \np{nn\_dynhpg\_rst} namelist parameter, so that the size of the 
     311via the  \np{nn_dynhpg_rst} namelist parameter, so that the size of the 
    312312restart file can be reduced when restartability is not a key issue (operational  
    313313oceanography or in ensemble simulations for seasonal forecasting). 
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