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Re: RR1h grib source?

Posted By: Peter Buckner
Date: 9-October-12 1532Z

In Response To: RR1h grib source? (Peter Buckner)

Follow up.... After some email exchanges with Bill @ NOAA, I believe I have an answer:

1) grid points don't align because of slightly different models for the earth. NCEP uses code table 3.2 #6 with assumed spherical radius = 6,371,229.0 meters, whereas this site (RR1h) uses code table 3.2 #0 with assumed spherical radius = 6,367,470.0 meters.

2) data values don't match because
a) Grid points are different, and
b) the model for RR1h is slightly different than the operational RAP at NCEP.

For comparison, one can access the Op40 sounding here, which are the NCEP RAP. The output from this website interpolates the NCEP 13km to the 40km grid, but the data matches.

So, it's all good & explainable. I'll let someone else figure out how big the earth is.

Thanks for your help, Bill!

-Peter Buckner
Aviation Weather
maps.AvnWx.com

Messages In This Thread

RR1h grib source? -- Peter Buckner -- 28-September-12 1747Z
Re: RR1h grib source? -- Peter Buckner -- 9-October-12 1532Z

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