Rapid Refresh (RAP) and High-Resolution Rapid Refresh (HRRR) Forum

Re: Hybrid Level In NWS/Comet Archive Of RAP Grids

Posted By: Stan Benjamin
Date: 30-May-13 1232Z

In Response To: Hybrid Level In NWS/Comet Archive Of RAP Grids (Ben Hamner)

Hello Ben, The (3-d) pressures on the RAP "hybrid-level" surfaces are the original pressures on the RAP native (original) coordinate surfaces, so they are exact. The 1-50 values correspond merely the vertical levels. The RAP uses a sigma vertical coordinate, and the "hybrid-level" GRIB label is a legacy from the RAP predecessor model, the RUC, which happened to use a hybrid isentropic-sigma vertical coordinate. Please write back if you still have a question. Stan Benjamin ------ Your original question: When I am reading the GRIB2 files from the NWS/Comet Archive of RAP Grids, I see 50 records each for the U Component of wind and V component of wind where the Fixed Surface Type is "105 - Hybrid Level". The corresponding values for this are 1-50. (For example, see http://soostrc.comet.ucar.edu/data/grib/rap/20130321/hybrid/13032100.rap.t00z.awp130bgrbf00.grib2) How precisely are these 1-50 level values converted back into the corresponding pressures? Previous posts on this are unclear, and there are no coordinates defined in the optional list of coordinate values.

Messages In This Thread

Hybrid Level In NWS/Comet Archive Of RAP Grids -- Ben Hamner -- 30-May-13 0036Z

ADMIN! Re: Hybrid Level In NWS/Comet Archive Of RAP Grids -- Stan Benjamin -- 30-May-13 1232Z

Re: Hybrid Level In NWS/Comet Archive Of RAP Grids -- Andrew -- 5-June-13 1917Z

rap@andrewpoh.fastmail.fm -- Andrew -- 10-June-13 2336Z

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