Domain & resolution
First you should decide upon the final(!) (see "Cascading" below) domain and resolution you want to run. For this it is important to know that:
- the more grid points a grid has => the more cores are needed
- the higher the resolution => the shorter the model timestep => the longer the runtime of the simulation
Have a look at the following wiki about how to set up a model grid: Set up a model grid
Number of points
Topology (MPI & OpenMP)
Resolution → timestep
The relation between the horizontal resolution and the model timestep is linear. Here are some examples:
| Resolution [degree] | Resolution [km] | model timestep [sec] | For GY grid |
|---|
| 0.009° | ~1 km | 30 s |
|
| 0.0225° | ~2.5 km | 60 s |
|
| 0.036° | ~4 km | 90 s |
|
| 0.11° | ~12 km | 300 s |
|
| ~25 km | 720 s | Grd_nj = 417
|
| ~55 km | 1800 s | Grd_nj = 171
|
Resolution → timestep → radiation timestep
Resolution → (non) hydrostatic
Model levels
LAM grid → top piloting or sponge
Global grid → adjust global pressure
Cascadeing
Spectral nudging
Period
Greenhouse gases / Scenario
Initial conditions
Driving data
Geophysical fields
Schemes
Land surface scheme (ISBA, CLASS, SVS)
Lake scheme (non, FLake, CSLM)
Urbain scheme (non, TEB)
Radiation
Roughness length
Limit ice /snow
Gravity wave drag
Emissivity
Condensation
Convection
Tracers to advect
Precipitation (Bourgouin)
Boundary layer
Horizontal diffusion
Output fields
Output fields
Instantaneous / averages / min / max
Initial condition fields
Pilot fields (2-D / 3-D)
Output frequency
Output levels
Size of output files (monthly/daily/hourly/...)
Submission
Wall clock time
Account