Offline nesting parameters

Since revision -r3347 a mesoscale nesting is available, which allows to nest a PALM domain within a mesoscale model. Therefore, time-dependent values for the three velocity components, potential temperature as well as the mixing ratio for the lateral and top boundaries of the PALM model domain are stored in the dynamic input file and are read and mapped onto the respective arrays during the simulation. This way, it is possible to account for evolving synoptic conditions during the simulation without adding further tendency terms or to nudge the LES solution. Please note, the mesoscale is designed as an inter-model one-way offline nesting where the mesoscale simulation runs in advance. The mesoscale offline nesting needs to be distinguished from PALM's self-nesting, which is designed as a two-way (one-way possible) model coupling between PALM simulations during the time-integration.

For a detailed detailed technical description of the mesoscale offline nesting we refer to < replace with doi when available >.

The current namelist has no parameters. Offline nesting is switched on by just adding an empty namelist to the namelist file:

 &nesting_offl_parameters  /

If offline nesting has been switched on, lateral and top boundary data for the velocity components, potential temperature and mixing_ratio (humidity) are read from the dynamic input file (see PIDS_DYNAMIC). Boundary data can be created with the preprocessor INIFOR, which is currently tailored towards the COSMO-model (other models will follow). Please note, offline nesting is only possible if a dynamic input file (see PIDS_DYNAMIC) is available.

Note, as the mesoscale model output does not contain turbulence, it needs to be imposed at the lateral inflow boundaries by employing the synthetic turbulence generator (see here) to trigger the spatial development of the turbulent flow .

NAMELIST group name: nesting_offl_parameters

Parameter Name	FORTRAN Type	Default Value	Explanation
switch_off_module	L	.F.