FNL Data

NCEP Global Analyses on 1x1 degree grids are available every six hours. The analyses are from the NCEP Final Analyses (FNL). These were operationally prepared by NCEP, but are available for download from NCAR/RDA.

For further information about the FNL archives at NCAR: See, http://rda.ucar.edu/datasets/ds083.2.

Type: GRIB2 data

Resolution:

1deg global data
Output frequency 6 hourly
34 pressure levels

Availability: These data are available at NCAR/RDA since July 30, 1999

From the web:
http://rda.ucar.edu/datasets/ds083.2
Follow the tab to "Data Access -> Internet Download". You must register (it is free) to access the data.
 

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 (Boulder, CO, U.S. Snowstorm, Nov. 2019)

These data are available for the period November 25 at 12 UTC, through November 27 at 00 UTC, 2019 (data frequency is 6 hourly).

Notes on running UNGRIB for this data

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

   tar xzvf boulder_snow_fnl.tar.gz

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

   ./util/g2print.exe ../DATA/boulder_snow/fnl_20191125_12_00.grib2

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


4. ./link_grib.csh ../DATA/boulder_snow/fnl_2019


5. Edit namelist.wps
   

   start_date = '2019-11-25_12:00:00',
   end_date = '2019-11-27_00:00:00',
   interval_seconds = 21600,
   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:2019-11-25_12
   ncl /util/plotfmt.ncl 'filename="FILE:2019-11-25_12"'