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CRUTEM3 gridder

The CRUTEM3 gridder makes a PP field from the station data for a selected month. The spatial resolution and extent of the field, and the parameter to be gridded, can be specified by the user.

User interface

The gridder program is gridcrut.perl. Command line options to control the gridding are given below.
Option Effect Allowed Values Default
--date Specifies the month to be gridded. yyyy/mm - Any year and month are allowed, but the gridding will fail if there is no monthly file for that month. None. This option is required.
--grid Specifies the parameter to be gridded:
  • mean - the mean temperature anomaly,
  • nobs - the number of obs,
  • sd - the temperature anomaly standard deviation,
  • station_sd - the mean station anomaly standard deviation,
  • sample_error - the sampling error of the temperature anomaly,
  • station_error - the station error of the temperature anomaly,
  • grid_error - sample_error+station_error.
All in degrees centigrade.
mean
--output_file Name of PP file produced by the gridder. Any legal file name grid.pp
--lat_resolution Grid resolution in latitude (degrees). Any integer divisor of the latitude range,
i.e. (lat_max-lat_min)/lat_resolution must be an integer.
5.0
--long_resolution Grid resolution in longitude (degrees) Any integer divisor of the longitude range 5.0
--min_lat Minimum latitude to be gridded (degrees, north positive). -90 to +90 -90
--min_long Minimum longitude to be gridded (degrees, east positive). -180 to 180 -180
--max_lat Maximum latitude to be gridded (degrees, north positive). -90 to 90, must be greater than min_lat 90
--max_long Maximum longitude to be gridded (degrees, east positive). -180 to 180, must be greater than min_long 180

Also available are two utility scripts:

Both scripts take the same set of options given above.

Details

Examples of use

gridcrut.perl --date=1969/01
will make a global grid of temperature anomalies at 5x5 degree resolution for January 1969 and store the resulting PP field in a file called grid.pp.

gridcrut.perl --date=1969/01 --grid=sd --min_lat=20 --max_lat=60 --lat_resolution=1.25 --min_long=-150 --max_long=-50.625 --long_resolution=1.875 --output_file=na_gem1.pp
will grid the temperature anomaly standard deviations over the North American region on the HadGEM1 atmosphere resolution and store the resulting PP field in a file called na_gem1.pp


Last updated: 2006/11/13
Maintained by: Philip Brohan.