met_check_dt
met_check_dt checks model time-step constraints for a meteorological
data file. It reports height-dependent estimates for horizontal and
vertical advection and diffusion time steps using the current MPTRAC
control parameters.
./met_check_dt <ctl> <dt_file> <met> [KEY VALUE ...]
Required arguments:
ctl: control parameter file.dt_file: output file for the time-step diagnostics.met: meteorological input file.
Optional trailing arguments can be used to override control parameters
on the command line as KEY VALUE pairs.
Relevant control parameters:
| parameter | purpose | default |
|---|---|---|
TURB_DX_PBL |
PBL horizontal diffusivity [m2/s] used for column $4 |
50 |
TURB_DX_TROP |
free-tropospheric horizontal diffusivity [m2/s] used for column $4 |
50 |
TURB_DX_STRAT |
stratospheric horizontal diffusivity [m2/s] used for column $4 |
0 |
TURB_DZ_PBL |
PBL vertical diffusivity [m2/s] used for column $5 |
0 |
TURB_DZ_TROP |
free-tropospheric vertical diffusivity [m2/s] used for column $5 |
0 |
TURB_DZ_STRAT |
stratospheric vertical diffusivity [m2/s] used for column $5 |
0.1 |
TURB_PBL_TRANS |
fractional depth of the PBL transition layer used for column $6 |
0 |
DX |
horizontal grid spacing [km] | required |
CMAX |
maximum Courant number for advection | 0.5 |
NMAX |
maximum stability factor for diffusion | 0.3 |
The output columns are:
$1: height [km]$2: time step for horizontal advection [s]$3: time step for vertical advection [s]$4: time step for horizontal diffusion [s] using layer-awareTURB_DX_*$5: time step for vertical diffusion [s] using layer-awareTURB_DZ_*$6: time step for resolving diffusion across the PBL transition layer [s]$7: time step for PBL diffusion on the full PBL-depth scale [s]
Columns $4 and $5 follow the same PBL/troposphere/stratosphere
weighting used by the fixed-K diffusion module. Column $6 is the
stricter transition-layer criterion and is only finite within the
configured PBL transition layer. Column $7 is a less conservative
PBL-scale criterion and is only finite within the PBL itself.
Example:
./met_check_dt trac.ctl dt_2011_06_05.tab ei_2011_06_05_00.nc DX 50 TURB_DZ_PBL 1.0 TURB_DZ_TROP 0.1 TURB_DZ_STRAT 0.1 TURB_PBL_TRANS 0.1