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NOTICE: This version of the NSF Unidata web site (archive.unidata.ucar.edu) is no longer being updated.
Current content can be found at unidata.ucar.edu.
To learn about what's going on, see About the Archive Site.
Art, I’ll send you my whole script. I’m maybe not doing something you are with the autoscaling or something. I am pretty sure I compared my calculated IR/WV results from the GRB data at least with the CSMI data coming over NOAAPORT and they are the same. I’m at my daughters gymnastics invite all day so may not be til tonight. Pete Sent from my iPhone On Jan 13, 2018, at 9:04 AM, Arthur A Person <aap1@xxxxxxx<mailto:aap1@xxxxxxx>> wrote: Pete, Thanks for the help. Actually, I already tried adding parens to the equation, including the variation you suggested, but the results are the same. Do you have a few lines of code that worked for you that you'd be willing to share? Or, do you recall whether there's any issue with netCDF auto-scaling the input data, or any units conversion that has to be included that's not in the documentation? Thanks... Art ________________________________ From: "Pete Pokrandt" <poker@xxxxxxxxxxxx<mailto:poker@xxxxxxxxxxxx>> To: "ARTHUR AUGUST PERSON" <aap1@xxxxxxx<mailto:aap1@xxxxxxx>>, "ldm-users" <ldm-users@xxxxxxxxxxxxxxxx<mailto:ldm-users@xxxxxxxxxxxxxxxx>> Sent: Friday, January 12, 2018 11:47:08 AM Subject: Re: [ldm-users] Problem calculating GOES-16 brightness temperature from radiance Art, I think it may be a parenthesis/order of operations issue. I seem to recall having this same issue when I first started working with the GRB data. Try this: bt = ( planck_fk2 / ( np.log((planck_fk1 / rad) + 1 )) - planck_bc1) / planck_bc2 Pete ________________________________ From: ldm-users-bounces@xxxxxxxxxxxxxxxx<mailto:ldm-users-bounces@xxxxxxxxxxxxxxxx> <ldm-users-bounces@xxxxxxxxxxxxxxxx<mailto:ldm-users-bounces@xxxxxxxxxxxxxxxx>> on behalf of Arthur A Person <aap1@xxxxxxx<mailto:aap1@xxxxxxx>> Sent: Friday, January 12, 2018 7:43 AM To: ldm-users@xxxxxxxxxxxxxxxx<mailto:ldm-users@xxxxxxxxxxxxxxxx> Subject: [ldm-users] Problem calculating GOES-16 brightness temperature from radiance Hi... I'm trying to calculate brightness temperature from radiance for GOES-16 IR channel 7 using rebroadcast data but my values compared to McIDAS imagery are coming out 15 to 20 degrees C too warm. I'm using the following values and code: Test imagery: OR_ABI-L1b-RadC-M3C07_G16_s20180112232223_e20180112235008_c20180112235045.nc rad (radiance) is read in from and auto-scaled by netCDF, planck_fk1: 202263.0 planck_fk2: 3698.18994140625 planck_bc1: 0.4336099922657013 planck_bc2: 0.9993900060653687 bt = ( planck_fk2 / np.log( (planck_fk1/rad)+1 ) - planck_bc1 ) / planck_bc2 bt = bt - 273.15 Can anyone tell me if I'm missing a step or spot a dumb mistake? Thanks... Art -- Arthur A. Person Assistant Research Professor, System Administrator Penn State Department of Meteorology and Atmospheric Science email: aap1@xxxxxxx<mailto:aap1@xxxxxxx>, phone: 814-863-1563 -- Arthur A. Person Assistant Research Professor, System Administrator Penn State Department of Meteorology and Atmospheric Science email: aap1@xxxxxxx<mailto:aap1@xxxxxxx>, phone: 814-863-1563
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