PROGRAM obs_selection

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$Id: obs_selection.html 6380 2013-08-05 23:47:11Z nancy $



This specialized tool selects out a subset of the input observations. For a more general purpose tool, see the obs_sequence_tool. The tool which creates the input selection file is obs_seq_coverage. This tool takes a selected list of observation types, times, and locations, and extracts only the matching observations out of a longer set of obs_sequence files.

The actions of the obs_selection program are controlled by a Fortran namelist, read from a file named input.nml in the current directory. A detailed description of each namelist item is described in the namelist section of this document. The names used in this discussion refer to these namelist items.



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.

   filename_seq          = 'obs_seq.out', 
   filename_seq_list     = '', 
   filename_out          = 'obs_seq.processed', 
   selections_file       = 'obsdef_mask.txt', 
   selections_is_obs_seq = .false.,
   print_only            = .false., 
   calendar              = "Gregorian",

Item Type Description
filename_seq character(len=129), dimension(500) The array of names of the observation sequence files to process, up to a max count of 500 files. (Specify only the actual number of input files. It is not necessary to specify 500 entries.)
filename_seq_list character(len=129) An alternative way to specify the list of input files. The name of a text file which contains, one per line, the names of the observation sequence files to process. You can only specify one of filename_seq OR filename_seq_list, not both.
num_input_files integer Optional. The number of observation sequence files to process. Maximum of 500. If 0, the length is set by the number of input files given. If non-zero, must match the given input file list length.
filename_out character(len=129) The name of the resulting output observation sequence file.
selections_file character(len=129) The name of the input file containing the mask of observation definitions (the textfile output of obs_seq_coverage).
print_only logical If .TRUE. do not create an output file, but print a summary of the number and types of each observation in each input file, and then the number of observations and types which would have been created in an output file.
calendar character(len=32) Set to the name of the calendar; only controls the printed output for the dates of the first and last observations in the file. Set this to "no_calendar" if the observations are not using any calendar.



Most $DART/models/*/work directories will build the tool along with other executable programs. It is also possible to build the tool in the $DART/observations/utilities directory. The preprocess program must be built and run first, to define what set of observation types will be supported. See the preprocess documentation for more details on how to define the list and run it. The combined list of all observation types which will be encountered over all input files must be in the preprocess input list. The other important choice when building the tool is to include a compatible locations module. For the low-order models, the oned module should be used; for real-world observations, the threed_sphere module should be used.

Generally the directories where executables are built will include a "quickbuild.csh" script which will build and run preprocess and then build the rest of the executables. The "input.nml" namelists will need to be edited to include all the required observation types first.









obs_selection num_input_files > max_num_input_files. change max_num_input_files in source file The default is 500 files.
obs_selection num_input_files and filename_seq mismatch The number of filenames does not match the filename count.





Long laundry list of things this tool could do, including:


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This open source software is provided by UCAR, "as is",
without charge, subject to all terms of use at

Contact: DART core group
Revision: $Revision: 6380 $
Source: $URL: $
Change Date: $Date: 2013-08-05 17:47:11 -0600 (Mon, 05 Aug 2013) $
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