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 an 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 >.

NAMELIST group name: nesting_offl_parameters

Parameter Name	FORTRAN Type	Default Value	Explanation
nesting_offline	L	.F.	Flag to enable the mesoscale offline nesting. If set to .TRUE., 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 COSOM-model (other models will follow). Please note, offline nesting is only possible if an dynamic input file (see PIDS_DYNAMIC) is available. Note, as the mesoscale model output does not contain turbulence, this need 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 .