MODULE DEFAULT_obs_def_mod

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$Id: DEFAULT_obs_def_mod.html 11832 2017-07-18 19:29:35Z nancy@ucar.edu $

TERMS OF USE

Overview

Beginning with the I-release of DART, a more flexible, powerful (and complicated) mechanism for incorporating new types of observations is part of DART. The DEFAULT_obs_def module being described here is used by the program preprocess to create obs_def_mod.f90.

To read more detailed instructions for adding your own new observation types, see the documentation for obs_def_mod. The process does not involve altering this DEFAULT_obs_def_mod.F90 file. Instead, new obs_def files are specified as input to the preprocess program by namelist, and a new obs_def_mod.f90 file is generated. The rest of the documentation here describes the internals of how the preprocess program uses the template file to do the code generation.

Information from zero or more special obs_def modules, such as obs_def_1d_state_mod.f90 or obs_def_reanalyis_bufr_mod.f90, (also documented in this directory) are incorporated into the template provided by DEFAULT_obs_def_mod. If no special obs_def files are included in the preprocessor namelist, a minimal obs_def_mod.f90 is created which can only support identity forward observation operators. Any identity observations on the obs_seq.out file will be assimilated, regardless of the obs types specified in assimilate_these_obs_types.

This documentation file only describes the special formatting that is included in the DEFAULT_obs_def_mod in order to guide the preprocess program. Up to seven sections of code are inserted into the DEFAULT_obs_def_mod from each of the special obs_def modules that are requested. The insertion point for each section is denoted by a special comment line that must be included VERBATIM in DEFAULT_obs_def_mod.F90. These special comment lines and their significance are:

  1. ! DART PREPROCESS MODULE CODE INSERTED HERE
    Some special observation definition modules (see for instance obs_def_1d_state_mod.f90) contain code for evaluating forward observation operators, reading or writing special information about an observation definition to an obs sequence file, or for interactive definition of an observation. The entire module code section is inserted here, so the resulting output file will be completely self-contained. Fortran 90 allows multiple modules to be defined in a single source file, and subsequent module code can use previously defined modules, so this statement must preceed the rest of the other comment lines.

  2. ! DART PREPROCESS USE FOR OBS_QTY_MOD INSERTED HERE
    Integer identifiers with a unique integer value corresponding to each available observation quantity are defined in a table in the obs_kind_mod which is also created by the preprocessor. The use statements for these entries are inserted here.

  3. ! DART PREPROCESS USE OF SPECIAL OBS_DEF MODULE INSERTED HERE
    Some special observation definition modules (see for instance obs_def_1d_state_mod.f90) contain code for evaluating forward observation operators, reading or writing special information about an observation definition to an obs sequence file, or for interactive definition of an observation. The use statements for these routines from the special observation definition modules are inserted here.

  4. ! DART PREPROCESS GET_EXPECTED_OBS_FROM_DEF INSERTED HERE
    Special observation definition modules must contain case statement code saying what to do to evaluate a forward observation operator for each observation type that they define. This code is inserted here.

  5. ! DART PREPROCESS READ_OBS_DEF INSERTED HERE
    Special observation definition modules must contain case statement code saying what to do to read any additional information required for each observation type that they define from an observation sequence file. This code is inserted here.

  6. ! DART PREPROCESS WRITE_OBS_DEF INSERTED HERE
    Special observation definition modules must contain case statement code saying what to do to write any additional information required for each observation type that they define to an observation sequence file. This code is inserted here.

  7. ! DART PREPROCESS INTERACTIVE_OBS_DEF INSERTED HERE
    Special observation definition modules must contain case statement code saying what to do to interactively create any additional information required for each observation type that they define. This code is inserted here.

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Terms of Use

DART software - Copyright UCAR. This open source software is provided by UCAR, "as is", without charge, subject to all terms of use at http://www.image.ucar.edu/DAReS/DART/DART_download

Contact: DART core group
Revision: $Revision: 11832 $
Source: $URL: https://svn-dares-dart.cgd.ucar.edu/DART/releases/Manhattan/observations/forward_operators/DEFAULT_obs_def_mod.html $
Change Date: $Date: 2017-07-18 13:29:35 -0600 (Tue, 18 Jul 2017) $
Change history:  try "svn log" or "svn diff"