Changes between Version 459 and Version 460 of doc/app/initialization_parameters

Timestamp:

Feb 25, 2020 1:55:04 PM (5 years ago)

Author:

oliver.maas

Comment:

--

doc/app/initialization_parameters

@@ -311 +311 @@
 '''Attention:'''\\
 The large-scale vertical motion is only applied to the prognostic equation for the scalar quantities (potential temperature, humidity if [#humidity humidity] = ''.T.'' or passive scalar if [#passive_scalar passive_scalar] = ''.T.''). It should not be applied to the momentum equations due to incompressibility. Applying it also to the horizontal velocity components would result in mass inconsistencies.
+
+'''Important:'''\\
+The application of a large-scale subsidence in the stably stratified free atmosphere leads to a general temperature increase which may result in a positive mean vertical velocity due to a positive mean buoyancy, if '''reference_state''' = '' 'initial_profile' ''. This is an unphysical result and may cause undesired effects (e.g. heat flux) at the domain top. It is recommended to use '''reference_state''' = '' 'horizontal_average' '' to avoid a positive mean buoyancy inside the domain. Setting the pressure boundary condition at the domain top to '''bc_p_t''' = '' 'neumann' '' ensures that the vertical acceleration and hence also the vertical velocity at the domain top is zero. Using '''psolver''' = '' 'poisfft' '' instead of '' 'multigrid' '' is also a solution to this problem.
 }}}
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