Making time averages is a common operation for a place with the word "climate" in its name. Consequently we are making available a time-averaging program for CORe. This will be useful if you are getting the 3 hourly files from the Nomads web site and you want to make daily or monthly means. The script will be useful if you want make weekly or other such means.

Time averaging would be a one-line command except for the 3 hourly T min, T max, SPFHmin and SPFHmax. For these four variables, you want to make 24 hour max/min values, and then make the average.

The program mk_core_mean.sh needs a list of 3 hourly CORe files in chronological order. The number of input files must be a multiple of 8 (even number of days). To make the time mean, you use the script mk_core_mean.sh.

$ mk_core_mean.sh OUTPUT.grb 3hr file1 file2 ... file8N

For mk_core_mean.sh to work, the programs wgrib2 and gmerge must be installed. Gmerge takes a list of CORe files and make temporal means. Gmerge is also used with wgrib2 to create the ensemble statistics.

Directions on using gmerge to make temporal and ensemble means. It's fun to see an old program (born 5/2009) being applied to a new problem (ensemble statistics).

mk_core_mean.sh
CORe home page
-new_grid
-new_grid_interpolation
-new_grid_winds

Comments: Wesley.Ebisuzaki@noaa.gov, Leigh.Zhang@noaa.gov
Created Sep 12, 2025