PROGRAM `ncommas_to_dart`

Attention

NCOMMAS works with versions of DART before Manhattan (9.x.x) and has yet to be updated. If you are interested in using NCOMMAS with more recent versions of DART, contact DAReS staff to assess the feasibility of an update. Until that time, you should consider this documentation as out-of-date.

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

PROGRAM ncommas_to_dart