GFS Data

GFS (Global Forecast System) is a model product from NCEP.

Type: GRIB1 / GRIB2 data

Resolution:

0.25 deg global data
Output frequency 3 hourly
34 pressure levels

Availability:

From NCAR's RDA site: https://rda.ucar.edu/datasets/ds084.1/
Since Jan 15, 2015

Vtable: Vtable.GFS

Peruse the ungrib/Variable_Tables/Vtable.GFS file to see which fields we are going to unpack from the GRIB files.

 

Sample data (Colorado, U.S. Blizzard, Nov-Dec. 2019)

These data are GRIB2, with output frequency of 3 hourly.
The data are available for the period November 29 at 12 UTC, through December 01 at 00 UTC, 2019.

Notes on running UNGRIB for this data

1. Download data and place in directory ../DATA/co_blizzard, and then unpack the file

   tar xzvf co_blizzard_0p25.tar.gz

2. Examine the GRIB files, e.g.,
   

   ./util/g2print.exe ../DATA/co_blizzard/gfs.0p25.2019112912.f000.grib2

3. ln -sf ungrib/Variable_Tables/Vtable.GFS Vtable


4. ./link_grib.csh ../DATA/co_blizzard/gfs.0p25.2019


5. Edit namelist.wps
   

   start_date = '2019-11-29_12:00:00',
   end_date = '2019-12-01_00:00:00',
   interval_seconds = 10800,
   prefix = 'FILE',
   

6. ./ungrib.exe

   This will create an ungrib.log for your records.



7. Examine the intermediate files, e.g.,
   

   ./util/rd_intermediate.exe FILE:2019-11-29_12
   ncl /util/plotfmt_ncl 'filename="FILE:2019-11-29_12"'