Marine stratocumulus clouds (FIRE)
Case description
The FIRE (First ISCCP Regional Experiment) case simulates marine stratocumulus clouds off the coast of California. This is a classic case for testing cloud-radiation interactions and LES modeling of marine boundary layer clouds. The case exists in two configurations: 1D (single column) and 3D (LES).
Warning
The 3D configuration requires MPI parallelization and the 1D configuration can only be run on a single core.
Configuration
Parameter |
1D (FIRE_1D) |
3D (FIRE) |
|---|---|---|
Category |
Idealized cases |
HPC cases |
Dynamics |
3D with 1D turbulence |
3D LES |
Horizontal grid spacing |
2500 m (1x1) |
50 m (50x50) |
Integration length |
90000 s (25 hours) |
90000 s (25 hours) |
Time step |
120 s |
1 s |
Coriolis effect |
enabled |
enabled |
Turbulence |
TKEL (1D) |
TKEL (3D) |
Cloud scheme |
KHKO |
KHKO |
Deep convection |
NONE |
NONE |
Radiation |
ECMWF |
ECMW |
LES diagnostics |
enabled |
enabled |
Declination
Configuration |
Cloud scheme |
Radiation |
|---|---|---|
FIRE_1D/KHKO |
KHKO |
ECMWF |
FIRE_1D/KHKO_MALA |
KHKO |
MALA |
FIRE_1D/LIMA_ECRAD |
LIMA |
ECRAD |
FIRE_1D/LIMA_MALA |
LIMA |
MALA |
FIRE/CEN4TH_RKC4 |
KHKO |
ECMW |
FIRE/CEN4TH_LEFR |
KHKO |
ECMW |
FIRE/CEN4TH_RKC4_LIMA_ECRAD |
LIMA |
ECRAD |
FIRE/WENO5 |
KHKO |
ECMW |
Steps
Step |
Script |
|---|---|
001_prep_ideal |
run_prep_ideal_case_xyz / run_prep_ideal |
002_mesonh |
run_mesonh_xyz / run_mesonh |
Specificities
Scientific specificities
Marine stratocumulus layer with cloud-top radiative cooling
Sea surface temperature: 289 K prescribed
July 14, 1987 initialization (25200s UTC)
Geostrophic forcing with vertical motion
Cloud-radiation interactions
Different turbulence length scales (BL89 for 1D, DEAR for 3D)
Technical specificities
1D: single point domain with 120 vertical levels
3D: 50x50 horizontal grid (2.5km x 2.5km domain)
Cyclic boundary conditions for 3D
Initial perturbation (0.1 m/s vertical for 3D)
Validation
Cloud fraction evolution
Liquid water path
Radiative fluxes
Turbulent fluxes
Numerical ressources
1D: Single CPU (1 node, 1 core) 3D: 4 nodes, 256 cores (MPI parallel)
References
Randall, D.A., et al. (1996): Intercomparison of stratocumulus cloud fields during FIRE. Mon. Wea. Rev., 124, 137-156.