PROGRAM ncommas_to_dart

ncommas_to_dart is the program that reads a ncommas restart file (usually ncommas_restart.nc) and creates a DART state vector file (e.g. perfect_ics, filter_ics, ... ).

The list of variables used to create the DART state vector are specified in the ncommas_vars.nml file.

Conditions required for successful execution of ncommas_to_dart:

• a valid input.nml namelist file for DART

• a valid ncommas_vars.nml namelist file for ncommas

• the ncommas restart file mentioned in the input.nml&model_nml:ncommas_restart_filename variable.

Since this program is called repeatedly for every ensemble member, we have found it convenient to link the ncommas restart files to the default input filename (ncommas_restart.nc). The default DART state vector filename is dart_ics - this may be moved or linked as necessary.

Namelist

This namelist is read from the file input.nml. Namelists start with an ampersand ‘&’ and terminate with a slash ‘/’. Character strings that contain a ‘/’ must be enclosed in quotes to prevent them from prematurely terminating the namelist.

&model_nml
   ncommas_restart_filename     = 'ncommas_restart.nc';
   assimilation_period_days     = 1,
   assimilation_period_seconds  = 0,
   model_perturbation_amplitude = 0.2,
   output_state_vector          = .true.,
   calendar                     = 'Gregorian',
   debug                        = 0
/

&ncommas_to_dart_nml
   ncommas_to_dart_output_file = 'dart_ics'
/

ncommas_to_dart_nml and model_nml are always read from a file called input.nml. The full description of the model_nml namelist is documented in the NCOMMAS model_mod.

Item	Type	Description
ncommas_to_dart_output_file	character(len=128)	The name of the DART file which contains the updated model state info that should be written into the NCOMMAS file.

ncommas_vars_nml is always read from a file called ncommas_vars.nml.

Item	Type	Description
ncommas_state_variables	character(len=NF90_MAX_NAME) :: dimension(160)	The list of variable names in the NCOMMAS restart file to use to create the DART state vector and their corresponding DART kind.

&ncommas_vars_nml
   ncommas_state_variables = 'U',   'QTY_U_WIND_COMPONENT',
                             'V',   'QTY_V_WIND_COMPONENT',
                             'W',   'QTY_VERTICAL_VELOCITY',
                             'TH',  'QTY_POTENTIAL_TEMPERATURE',
                             'DBZ', 'QTY_RADAR_REFLECTIVITY',
                             'WZ',  'QTY_VERTICAL_VORTICITY',
                             'PI',  'QTY_EXNER_FUNCTION',
                             'QV',  'QTY_VAPOR_MIXING_RATIO',
                             'QC',  'QTY_CLOUDWATER_MIXING_RATIO',
                             'QR',  'QTY_RAINWATER_MIXING_RATIO',
                             'QI',  'QTY_ICE_MIXING_RATIO',
                             'QS',  'QTY_SNOW_MIXING_RATIO',
                             'QH',  'QTY_GRAUPEL_MIXING_RATIO'
  /

Modules used

assim_model_mod
location_mod
model_mod
null_mpi_utilities_mod
obs_kind_mod
random_seq_mod
time_manager_mod
types_mod
utilities_mod

Files read

• ncommas restart file; ncommas_restart.nc

• DART namelist files; input.nml and ncommas_vars.nml

Files written

• DART state vector file; e.g. dart_ics

References

none