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 <ldm-users-bounces@xxxxxxxxxxxxxxxx>
on behalf of Arthur A Person <aap1@xxxxxxx>
Sent: Friday, January 12, 2018 7:43 AM
To: 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, phone: 814-863-1563
