GABLS1
Case description
The GABLS1 (GEWEX Atmospheric Boundary Layer Study) case simulates a stable boundary layer over Arctic land during winter. This case tests the model ability to reproduce nocturnal boundary layer turbulence and low-level jets.
Configuration
Parameter |
1D |
3D |
|---|---|---|
Category |
HPC cases |
HPC cases |
Dynamics |
3D with 1D turbulence |
3D LES |
Horizontal grid spacing |
2 m (1x1) |
2 m (100x100) |
Integration length |
32400 s (9 hours) |
32400 s (9 hours) |
Time step |
10 s |
0.2 s |
Coriolis effect |
enabled |
enabled |
Turbulence |
TKEL (1D) |
TKEL (3D) |
Cloud scheme |
NONE |
NONE |
Radiation |
NONE |
NONE |
LES diagnostics |
enabled |
enabled |
Declination
Configuration |
Turbulence |
Description |
|---|---|---|
GABLS1/1D/BL89 |
TKEL (BL89) |
1D with Blackadar length scale |
GABLS1/1D/RM17 |
TKEL (RM17) |
1D with RM17 length scale |
GABLS1/3D |
TKEL (DEAR) |
3D LES |
Steps
Step |
Script |
|---|---|
001_prep_ideal |
run_prep_ideal_case |
002_mesonh |
run_mesonh |
Specificities
Scientific specificities
Stable boundary layer with sustained cooling
Weak surface temperature gradient (-0.25 K for first 8 hours)
Geostrophic forcing (8 m/s)
Low-level jet development
Very high vertical resolution (2m near surface, stretching to 6m)
155 vertical levels
Technical specificities
1D: single point domain (1x1 grid), two turbulence variants (BL89, RM17)
3D: 100x100 horizontal grid with DEAR length scale
ISBA surface scheme for snow/ice
Arctic location (73°N)
Validation
Turbulent heat flux profiles
Temperature evolution
Wind profile (low-level jet)
Boundary layer height
Numerical ressources
1D: Single CPU (1 node, 1 core) 3D: 4 nodes, 256 cores (MPI parallel)
References
GABLS1 intercomparison study (Beare et al., 2006)