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[Datastream #OMB-868480]: GOES-10 McIDAS data



Hi Stacy,

re:
> One more thing . . . I've found some information online that describes
> how to convert the goes12 imager counts to radiance and then to
> temperature, but they're all based on 10bit raw count values.  Are there
> look-up tables for the 8bit data, or should I just mulitply the values
> in the 8bit files by 4 and use the existing instructions

The 1-byte images broadcast in the Unidata-Wisconsin datastream (IDD feedtype
UNIWISC aka MCIDAS) are pre-calibrated: the mapping of brightness (0-255) to
temperature (K) is represented by the following two-slope relationship:

T[K]        BRIT (0-255)
-----       ------
 163           255
 241.9999      177
 242           176
 330           0

i.e.:

163 K      <-> 255 brightness
241.9999 K <-> 177 brightness
242 K      <-> 176 brightness
330 K      <->   0 brightness

This relationship holds for all IR channels (3.9 um, 6.5 um (GOES-12) or 6.8 um 
(GOES-10),
10.7 um, and 13.3 um (GOES-12) or 12.0 um (GOES-10).

> . . . in other
> words, replace "X" in the equations below with (X*4)??

You should use the two slope relationship above.

> These are the equations I found:
> 
> R = (X - b)/m, where R=radiance, X = GVAR count, m and b = constants
> 
> T(eff) = (c2 * n) / (ln [1 + (c1 * n^3)/R), T(eff) = effective temp, R =
> radiance, c1, c2, & n = constants
> 
> T = a + b * T(eff), T = actual temp, T(eff) = effective temp, a & b =
> constants
> 
> Thanks.

No worries.

Cheers,

Tom
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Ticket Details
===================
Ticket ID: OMB-868480
Department: Support Datastream
Priority: Normal
Status: Closed


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