HRRR Cloud Base and Ceiling Methodology #56
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I have been doing verification work recently of HRRR cloud base and ceiling and wanted to verify the exact methodology that goes into the calculation of cloud base and ceiling as well as the low cloud cover product as it has been difficult to find clear documentation. Any help or description would be appreciated! |
Replies: 1 comment
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@michaelsessa1 you can find descriptions of the calculations in this Tech Memo: https://rapidrefresh.noaa.gov/Diag-vars-NOAA-TechMemo.pdf The cloud-related fields start on p. 31. If you are interested in looking at the actual code, you can find it in the Unified Post Processor (UPP) code on Github: https://github.com/NOAA-EMC/UPP The relevant code for the cloud base and ceiling is in CLDRAD.f, and you can search for parameter "711" (cloud base) and parameter "408" (ceiling). Low cloud cover comes from the explicit subgrid clouds in the MYNN boundary layer scheme. You can see in the code that it is simply multiplied by 100 (to put it into a percentage) and then output in GRIB2 (search for parameter "037"). |
@michaelsessa1 you can find descriptions of the calculations in this Tech Memo:
https://rapidrefresh.noaa.gov/Diag-vars-NOAA-TechMemo.pdf
The cloud-related fields start on p. 31. If you are interested in looking at the actual code, you can find it in the Unified Post Processor (UPP) code on Github:
https://github.com/NOAA-EMC/UPP
The relevant code for the cloud base and ceiling is in CLDRAD.f, and you can search for parameter "711" (cloud base) and parameter "408" (ceiling).
Low cloud cover comes from the explicit subgrid clouds in the MYNN boundary layer scheme. You can see in the code that it is simply multiplied by 100 (to put it into a percentage) and then output in GRIB2 (search for …