I use the GFS files as input in WRF, but I get an error when I try to change p_top_requested from 5000 to 1000 hPa. Kindly suggest.
Note that, p_top_requested must be Less than the minimum barometric pressure layer of GFS.
Thanks a lot Haiquing for the response. But how do I find the minimum pressure layer of my GFS file? And is it possible to obtain GFS files with lesser than 50 hPa? Thanks.
Jaya Thakur GFS model has updated several times. About 5 years ago，GFS data has 27 levels in vertical. Before June of 2019，GFS-v14 has 32 levels . And the recent update is in June of 2019. The core of GFS was replaced by new model--FV3-GFS. New data Parameter is here:https://www.nco.ncep.noaa.gov/pmb/products/gfs/gfs.t00z.pgrb2.0p50.f003.shtml
May be usfull to you.
NCEP is upgrading GFS from version 14 to 15.1 beginning with the 1200 UTC run on June 12, 2019. At that time, there will also be a chance with the real-time data product. This includes available pressure levels, file size, and the data directory structure. For the data directory change and the full description of the GFS upgrade, please see https://www.weather.gov/media/notification/scn19-40gfs_v15_1.pdf To handle the new GFS data, you must use the ungrib program from WPS V4.0 or later. You do not need to upgrade other programs to later versions. The output from the newer ungrib will work with metgrid and the WRF model from earlier versions. To do so, you can download WPS Version 4.0 or later, place it in appropriate directory, then type 'configure' and 'compile ungrib'. This will only build the program ungrib.exe. After you run metgrid, check the values for 'num_metgrid_levels' using ncdump. If you do not use the supplementary pressure level data, num_metgrid_levels will change (from 32) to 34 with the new data. You can also use the new namelist option pmin (unit Pa) for ungrib to limit the pressure level data ungrib processes. If you set pmin = 1000, then you will get 29 pressure levels.
Haiquing Soong, thank you so much for the response. It was really very informative.
I am using WPS version 3.8.1 for Dec 2018 GFS data. I tried implementing the pmin parameter in this version, but the run did not go through. ncdump gives me the num_metgrid_levels as 32 for Dec 2018 GFS file, but I am still not able to reach a similar elaborate list of parameters as provided by you for beyond June 2019.
Can you please suggest as to where I get such a list and how I can manipulate to obtain outputs beyond 5000 Pa (as set in p_top_requested=5000).
Thanks in advance again.
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