Changeset 11577 for NEMO/trunk/doc/latex/NEMO/subfiles/chap_time_domain.tex
- Timestamp:
- 2019-09-19T19:01:38+02:00 (5 years ago)
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NEMO/trunk/doc/latex/NEMO/subfiles/chap_time_domain.tex
r11567 r11577 85 85 \end{equation} 86 86 where the subscript $F$ denotes filtered values and $\gamma$ is the Asselin coefficient. 87 $\gamma$ is initialized as \np{rn \_atfp} (namelist parameter).88 Its default value is \np{rn \_atfp}\forcode{ = 10.e-3} (see \autoref{sec:TD_mLF}),87 $\gamma$ is initialized as \np{rn_atfp}{rn\_atfp} (namelist parameter). 88 Its default value is \np{rn_atfp}{rn\_atfp}\forcode{ = 10.e-3} (see \autoref{sec:TD_mLF}), 89 89 causing only a weak dissipation of high frequency motions (\citep{farge-coulombier_phd87}). 90 90 The addition of a time filter degrades the accuracy of the calculation from second to first order. … … 172 172 173 173 The leapfrog environment supports a centred in time computation of the surface pressure, \ie\ evaluated 174 at \textit{now} time step. This refers to as the explicit free surface case in the code (\np{ln \_dynspg\_exp}\forcode{=.true.}).174 at \textit{now} time step. This refers to as the explicit free surface case in the code (\np{ln_dynspg_exp}{ln\_dynspg\_exp}\forcode{=.true.}). 175 175 This choice however imposes a strong constraint on the time step which should be small enough to resolve the propagation 176 176 of external gravity waves. As a matter of fact, one rather use in a realistic setup, a split-explicit free surface 177 (\np{ln \_dynspg\_ts}\forcode{=.true.}) in which barotropic and baroclinic dynamical equations are solved separately with ad-hoc177 (\np{ln_dynspg_ts}{ln\_dynspg\_ts}\forcode{=.true.}) in which barotropic and baroclinic dynamical equations are solved separately with ad-hoc 178 178 time steps. The use of the time-splitting (in combination with non-linear free surface) imposes some constraints on the design of 179 179 the overall flowchart, in particular to ensure exact tracer conservation (see \autoref{fig:TD_TimeStep_flowchart}). … … 297 297 When restarting, if the time step has been changed, or one of the prognostic variables at \textit{before} time step 298 298 is missing, an Euler time stepping scheme is imposed. A forward initial step can still be enforced by the user by setting 299 the namelist variable \np{nn \_euler}\forcode{=0}. Other options to control the time integration of the model299 the namelist variable \np{nn_euler}{nn\_euler}\forcode{=0}. Other options to control the time integration of the model 300 300 are defined through the \nam{run} namelist variables. 301 301 %%%
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