PROGRAM `model_to_dart` for MPAS OCN

Attention

mpas_ocn was being developed with versions of DART before Manhattan (9.x.x) and has yet to be updated. If you are interested in using mpas_ocn 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 Until that time, you should consider this documentation as out-of-date.

Overview

model_to_dart is the program that reads an MPAS OCN analysis file (nominally named mpas_restart.nc) and creates a DART state vector file (e.g. perfect_ics, filter_ics, ... ). The MPAS analysis files have a Time UNLIMITED Dimension, which indicates there may (at some point) be more than one timestep in the file. The DART routines are currently designed to use the LAST timestep. If the Time dimension of length 3, we use the third timestep. A warning message is issued and indicates exactly the time being used.

input.nml&mpas_vars_nml defines the list of MPAS variables used to build the DART state vector. This namelist is more fully described in the MPAS OCN documentation. For example:

&mpas_vars_nml
   mpas_state_variables = 'temperature',  'QTY_TEMPERATURE',
                          'salinity',     'QTY_SALINITY',
                          'rho',          'QTY_DENSITY',
                          'u',            'QTY_EDGE_NORMAL_SPEED',
                          'h',            'QTY_SEA_SURFACE_HEIGHT'
                          'tracer1',      'QTY_TRACER_CONCENTRATION'
   /

Conditions required for successful execution of model_to_dart are:

a valid input.nml namelist file for DART which contains
a MPAS OCN analysis file (nominally named mpas_analysis.nc).

Since this program is called repeatedly for every ensemble member, we have found it convenient to link the MPAS OCN analysis files to a static input filename (e.g. mpas_analysis.nc). The default DART 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_to_dart_nml
   model_to_dart_output_file = 'dart_ics'
   /

&model_nml
   model_analysis_filename  = 'mpas_analysis.nc'
   /

(partial namelist)

&mpas_vars_nml
   mpas_state_variables = '',
   mpas_state_bounds = '',
   /

The model_to_dart namelist includes:

Item	Type	Description
model_to_dart_output_file	character(len=128)	The name of the DART file containing the model state derived from the MPAS analysis file.

Two more namelists need to be mentioned. The model_nml namelist specifies the MPAS analysis file to be used as the source. The mpas_vars_nml namelist specifies the MPAS variables that will comprise the DART state vector.

For example:

&mpas_vars_nml
   mpas_state_variables = 'temperature',  'QTY_TEMPERATURE',
                          'salinity',     'QTY_SALINITY',
                          'rho',          'QTY_DENSITY',
                          'u',            'QTY_EDGE_NORMAL_SPEED',
                          'h',            'QTY_SEA_SURFACE_HEIGHT'
                          'tracer1',      'QTY_TRACER_CONCENTRATION'
   /

Modules used

assim_model_mod.f90
types_mod.f90
location_mod.f90
model_to_dart.f90
model_mod.f90
null_mpi_utilities_mod.f90
obs_kind_mod.f90
random_seq_mod.f90
time_manager_mod.f90
utilities_mod.f90

Files read

MPAS analysis file; mpas_analysis.nc
DART namelist file; input.nml

Files written

DART initial conditions/restart file; e.g. dart_ics

References

none

PROGRAM model_to_dart for MPAS OCN