[Wrf-users] Availability of GFS data up to 1 mb

Eric Altshuler ela at cola.iges.org
Sat Jan 10 23:58:56 MST 2009

Dear Jordan,

I am interested in running the WRF model with the model top at 1 mb, using 0.5 degree GFS initial and lateral boundary conditions. To be able to have the model top this high, GFS data is required up to 1 mb. As far as I'm aware, 0.5 degree GFS data is only available up to 10 mb in the standard 'gfs.tHHz.pgrb2fFH' GRIB-2 files, but I have discovered that data is available up to 1 mb through the "OpenDAP" interface on nomads.ncep.noaa.gov (the data is also available on 47 pressure levels instead of the usual 26). However, for running WRF, I need GRIB data. I have three questions regarding this:

1. Are there any GRIB-2 files that include the GFS fields above 10 mb, up to 1 mb?

2. Are there any GRIB-2 files that have GFS data on all 47 pressure levels, rather than the subset of 26?

3. If the files in the above two questions exist, is there any archive of them? I am interested in running cases from May through October 2008. At COLA, we have an archive of 0.5 degree GFS GRIB-2 data covering this period, but the files we receive only have data up to 10 mb on 26 pressure levels.

I vaguely recall a discussion some time ago about 'a', 'b' and 'master' GFS files, and I am under the impression that the 'a' files are actually the 'gfs.tHHz.pgrb2fFH' files (i.e. the files we receive at COLA), but what data is contained in the 'b' and 'master' files, and are these files archived anywhere?

Thanks in advance for your attention.

Best regards,

Eric L. Altshuler
Assistant Research Scientist
Center for Ocean-Land-Atmosphere Studies
4041 Powder Mill Road, Suite 302
Calverton, MD 20705-3106

E-mail: ela at cola.iges.org
Phone: (301) 902-1257
Fax: (301) 595-9793

P.S. To the WRF user community, has anyone tried to run WRF with the model top as high as 1 mb? Is it advisable to run WRF with a vertical domain extending this far into the stratosphere? The default WRF model top is at 50 mb, and I've always wondered why the default model top is so low. Is there a specific reason for this?

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