Available observation converter programs
========================================

The ``DART/observations/obs_converters`` directory contains a variety of
converter programs to read various external formats and convert the observations
into the format required by DART.

Each directory has at least one converter:

-  ``AIRS``: :doc:`/observations/obs_converters/AIRS/README`
-  ``AURA``: See ``DART/observations/obs_converters/AURA``
-  ``Aviso+/CMEMS``: :doc:`../observations/obs_converters/AVISO/AVISO`
-  ``Ameriflux``: :doc:`../observations/obs_converters/Ameriflux/level4_to_obs`
-  ``BATS``: :doc:`../observations/obs_converters/BATS/readme`
-  ``CHAMP``: :doc:`../observations/obs_converters/CHAMP/work/README`
-  ``cice``: :doc:`../observations/obs_converters/cice/cice_to_obs`
-  ``CNOFS``: See ``DART/observations/obs_converters/CNOFS``
-  ``CONAGUA``: :doc:`../observations/obs_converters/CONAGUA/README`
-  ``COSMOS``: :doc:`../observations/obs_converters/COSMOS/COSMOS_to_obs`
-  ``DWL``: :doc:`../observations/obs_converters/DWL/dwl_to_obs`
-  ``GMI``: :doc:`../observations/obs_converters/GMI/README`
-  ``GOES``: :doc:`../observations/obs_converters/GOES/README`
-  ``GPSPW``: :doc:`../observations/obs_converters/GPSPW/README`
-  ``GRACE``: See ``DART/observations/obs_converters/GRACE``
-  ``GSI2DART``: :doc:`../observations/obs_converters/GSI2DART/readme`
-  ``GTSPP``: :doc:`../observations/obs_converters/GTSPP/GTSPP`
-  ``MADIS``: :doc:`../observations/obs_converters/MADIS/MADIS`
-  ``MIDAS``: :doc:`../observations/obs_converters/MIDAS/MIDAS_to_obs`
-  ``MODIS``: :doc:`../observations/obs_converters/MODIS/MOD15A2_to_obs`
-  ``MPD``: See ``DART/observations/obs_converters/MPD``
-  ``NCEP``: (prepbufr -> ascii) :doc:`../observations/obs_converters/NCEP/prep_bufr/prep_bufr`
-  ``NCEP``: (ascii -> obs_seq) :doc:`../observations/obs_converters/NCEP/ascii_to_obs/create_real_obs`
-  ``ROMS``: :doc:`../observations/obs_converters/ROMS/ROMS`
-  ``SIF``: :doc:`../observations/obs_converters/SIF/SIF_to_obs_netcdf`
-  ``SSEC``: :doc:`../observations/obs_converters/SSEC/SSEC`
-  ``SST``: :doc:`../observations/obs_converters/SST/SST`
-  ``SSUSI``: :doc:`../observations/obs_converters/SSUSI/convert_f16_edr_dsk`
-  ``WOD``: :doc:`../observations/obs_converters/WOD/WOD`
-  ``gnd_gps_vtec``: :doc:`../observations/obs_converters/gnd_gps_vtec/README`
-  ``GPS``: :doc:`../observations/obs_converters/gps/gps`
-  ``ok_mesonet``: :doc:`../observations/obs_converters/ok_mesonet/ok_mesonet`
-  ``QuikSCAT``: :doc:`../observations/obs_converters/quikscat/QuikSCAT`
-  ``Radar``: :doc:`../observations/obs_converters/radar/README`
-  ``snow``: :doc:`../observations/obs_converters/snow/snow_to_obs`
-  ``Text``: :doc:`../observations/obs_converters/text/text_to_obs`
-  ``text_GITM``: See ``DART/observations/obs_converters/text_GITM``
-  ``tpw``: :doc:`../observations/obs_converters/tpw/tpw`
-  ``Tropical Cyclones``: :doc:`../observations/obs_converters/tropical_cyclone/tc_to_obs`
-  ``Var (little-r)``: :doc:`../observations/obs_converters/var/littler_tf_dart`
-  ``Var (radar)``: :doc:`../observations/obs_converters/var/rad_3dvar_to_dart`

There are also a couple utilities of note:

-  :doc:`../observations/obs_converters/even_sphere/README` - a utility for generating evenly-spaced
   observation locations that can then be used in a perfect model experiment.
-  :doc:`../observations/obs_converters/obs_error/README` - modules that specify observation errors
   based on what is used by ECMWF and NCEP

In addition the following external program produces DART observation sequence
files:

-  `Observation Processing And Wind Synthesis
   (OPAWS) <http://code.google.com/p/opaws/>`__: OPAWS can process NSF NCAR Dorade
   (sweep) and NSF NCAR EOL Foray (netCDF) radar data. It analyzes (grids) data in
   either two-dimensions (on the conical surface of each sweep) or
   three-dimensions (Cartesian). Analyses are output in netCDF, Vis5d, and/or
   DART (Data Assimilation Research Testbed) formats.

For generating synthetic observations, see the documentation for the 
:doc:`../assimilation_code/programs/create_obs_sequence/create_obs_sequence`.
You can also generate observation files based on text input. See the
documentation for the :doc:`../observations/obs_converters/text/text_to_obs`.
Or for simulating a large complex observing system, you can use the DART
library routines in a Fortran program to compute the observation information
and have the DART routines write the output file.

To learn how to run a model with a set of observations that have only
locations, types, and times, and have the forward operators compute the
observation values, see the documentation for the
:doc:`/assimilation_code/programs/perfect_model_obs/perfect_model_obs`.