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20000814: Composites with gempak-format files

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  • Subject: 20000814: Composites with gempak-format files
  • Date: Tue, 15 Aug 2000 10:29:26 -0600
>From: Luis Farfan <address@hidden>
>Organization: UCAR/Unidata
>Keywords: 200008142318.e7ENITN20037

>Hi,
>
>I would like to have some advice regarding the way(s) I can approach to
>perform a composite analysis of the ETA model forecasts (AWIPS grid 211).
>
>I have a set of files in GEMPAK format with forecasts during a month and I
>would like to compute mean fields with the forecasts at at given time. For
>example, the 500 mb winds at F00 and the accumulated precipitation during
>the period F00-F06.
>
>So far, I have not seen a unique gempak program that allows me to perform
>these composites and, perhaps, I may need to combine several programs to
>obtain the required results. But before I start to build these
>combinations, I would like to have your comments about my options.
>
>Thank you, 
>
>       Luis M Farfan.
>       Dept. Atmospheric Sciences
>       University of Arizona.
>


Luis,

The program GDSTAT computes the average, standard deviation, and number
of reporting times at each grid point for a time series of grids.

You will want to use GDMOD to copy each field from separate files
to a single file for use with GDSTAT. You can create an empty file
with grid 211 projection with GDCFIL using CPYFIL=#211. Then,
for each file you have, use GDMOD to copy the HGHT@500 at F000 and P06M
for F006 into the new output file.

GDSTAT will compute fields named HGHT_AVE, HGHT_CNT and HGHT_STD etc
for each parameter you chose.

Steve Chiswell