PROGRAM wrf_dart_obs_preprocess

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$Id: wrf_dart_obs_preprocess.html 6404 2013-08-13 20:43:05Z nancy $

NAMELIST / MODULES / FILES / REFERENCES / ERRORS / PLANS / TERMS OF USE

Overview

Program to preprocess observations, with specific knowledge of the WRF domain.

This program will exclude all observations outside of the given WRF domain. There are options to exclude or increase the error values of obs close to the domain boundaries. The program can superob (average) aircraft and satellite wind obs if they are too dense.

This program can read up to 9 additional obs_seq files and merge their data in with the basic obs_sequence file which is the main input.

This program can reject surface observations if the elevation encoded in the observation is too different from the wrf surface elevation.

This program can exclude observations above a specified height or pressure.

This program can overwrite the incoming Data QC value with another.

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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.

&wrf_obs_preproc_nml

  file_name_input          = 'obs_seq.old'
  file_name_output         = 'obs_seq.new'
  
  sonde_extra              = 'obs_seq.rawin'
  land_sfc_extra           = 'obs_seq.land_sfc'
  metar_extra              = 'obs_seq.metar'
  marine_sfc_extra         = 'obs_seq.marine'
  sat_wind_extra           = 'obs_seq.satwnd'
  profiler_extra           = 'obs_seq.profiler'
  gpsro_extra              = 'obs_seq.gpsro'
  acars_extra              = 'obs_seq.acars'
  trop_cyclone_extra       = 'obs_seq.tc'
  
  overwrite_obs_time       = .false.  
  
  obs_boundary             = 0.0
  increase_bdy_error       = .false.  
  maxobsfac                = 2.5   
  obsdistbdy               = 15.0  
  
  sfc_elevation_check      = .false.  
  sfc_elevation_tol        = 300.0  
  obs_pressure_top         = 0.0  
  obs_height_top           = 2.0e10  
  
  include_sig_data         = .true.   
  tc_sonde_radii           = -1.0  
  
  superob_aircraft         = .false.  
  aircraft_horiz_int       = 36.0  
  aircraft_pres_int        = 2500.0  
  
  superob_sat_winds        = .false.    
  sat_wind_horiz_int       = 100.0   
  sat_wind_pres_int        = 2500.0  
  
  overwrite_ncep_satwnd_qc = .false.    
  overwrite_ncep_sfc_qc    = .false.  
/


Item Type Description
Generic parameters:
file_name_input character(len=129) The input obs_seq file.
file_name_output character(len=129) The output obs_seq file.
sonde_extra, land_sfc_extra, metar_extra, marine_sfc_extra, marine_sfc_extra, sat_wind_extra, profiler_extra, gpsro_extra, acars_extra, trop_cyclone_extra character(len=129) The names of additional input obs_seq files, which if they exist, will be merged in with the obs from the file_name_input obs_seq file. If the files do not exist, they are silently ignored without error.
overwrite_obs_time logical If true, replace the incoming observation time with the analysis time. Not recommended.
Boundary-specific parameters:
obs_boundary real(r8) Number of grid points around domain boundary which will be considered the new extent of the domain. Observations outside this smaller area will be excluded.
increase_bdy_error logical If true, observations near the domain boundary will have their observation error increased by maxobsfac.
maxobsfac real(r8) If increase_bdy_error is true, multiply the error by a ramped factor. This item sets the maximum error.
obsdistbdy real(r8) If increase_bdy_error is true, this defines the region around the boundary (in number of grid points) where the observation error values will be altered. This is ramped, so when you reach the innermost points the change in observation error is 0.0.
Parameters to reduce observation count :
sfc_elevation_check logical If true, check the height of surface observations against the surface height in the model.
sfc_elevation_tol real(r8) If sfc_elevation_check is true, the maximum difference between the elevation of a surface observation and the model surface height, in meters. If the difference is larger than this value, the observation is excluded.
obs_pressure_top real(r8) Observations with a vertical coordinate in pressure which are located above this pressure level (i.e. the obs vertical value is smaller than the given pressure) will be excluded.
obs_height_top real(r8) Observations with a vertical coordinate in height which are located above this height value (i.e. the obs vertical value is larger than the given height) will be excluded.
Radio/Rawinsonde-specific parameters :
include_sig_data logical If true, include significant level data from radiosondes.
tc_sonde_radii real(r8) If greater than 0.0 remove any sonde observations closer than this distance in Kilometers to the center of a Tropical Cyclone.
Aircraft-specific parameters :
superob_aircraft logical If true, average all aircraft observations within the given radius and output only a single observation. Any observation that is used in computing a superob observation is removed from the list and is not used in any other superob computation.
aircraft_horiz_int real(r8) If superob_aircraft is true, the horizontal distance in Kilometers which defines the superob area. All other unused aircraft observations within this radius will be averaged with the current observation.
aircraft_vert_int real(r8) If superob_aircraft is true, the vertical distance in Pascals which defines the maximum separation for including an observation in the superob computation.
Satellite Wind-specific parameters :
superob_sat_winds logical If true, average all sat_wind observations within the given radius and output only a single observation. Any observation that is used in computing a superob observation is removed from the list and is not used in any other superob computation.
sat_wind_horiz_int real(r8) If superob_sat_winds is true, the horizontal distance in Kilometers which defines the superob area. All other unused sat_wind observations within this radius will be averaged with the current observation.
sat_wind_vert_int real(r8) If superob_sat_winds is true, the vertical distance in Pascals which defines the maximum separation for including an observation in the superob computation.
overwrite_ncep_satwnd_qc logical If true, replace the incoming Data QC value in satellite wind observations with 2.0.
Surface Observation-specific parameters :
overwrite_ncep_sfc_qc logical If true, replace the incoming Data QC value in surface observations with 2.0.


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MODULES USED

types_mod
obs_sequence_mod
utilities_mod
obs_kind_mod
time_manager_mod
model_mod
netcdf
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FILES

File formats

This utility can read one or more obs_seq files and combine them while doing the rest of the processing. It uses the standard DART observation sequence file format.

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REFERENCES

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ERROR CODES and CONDITIONS

Routine Message Comment
wrf_dart_obs_preprocess
wrf_dart_obs_preprocess
wrf_dart_obs_preprocess
wrf_dart_obs_preprocess

KNOWN BUGS

none

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FUTURE PLANS

none.

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Terms of Use

DART software - Copyright 2004 - 2013 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: Glen Romine, Nancy Collins
Revision: $Revision: 6404 $
Source: $URL: https://svn-dares-dart.cgd.ucar.edu/DART/releases/classic/models/wrf/WRF_DART_utilities/wrf_dart_obs_preprocess.html $
Change Date: $Date: 2013-08-13 14:43:05 -0600 (Tue, 13 Aug 2013) $
Change history:  try "svn log" or "svn diff"