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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.

./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
KX horizontal diffusivity [m2/s] 50.0
KZ vertical diffusivity [m2/s] 0.1
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]
  • $5: time step for vertical diffusion [s]

Example:

./met_check_dt trac.ctl dt_2011_06_05.tab ei_2011_06_05_00.nc DX 50