Characteristics of GOES-13 Sounder IR Detectors Dejiang Han December 22, 2006

Comparisons of Spectral Response Functions for GOES-12 and GOES-13 Sounders (Channels 1 – 9) GOES-12 GOES-13

Comparisons of Spectral Response Functions for GOES-12 and GOES-13 Sounders (Channels 10 – 18) GOES-12 GOES-13

Striping Due to SRF Differences (Channels 1 – 9) ITT provides temperature-to-radiance conversion coefficients, which are determined with the detector spectral response functions. The coefficients are used in the GOES SPS data processing. Plots presented on this page and next show the GVAR count differences within a channel. The difference for each detector is defined as Value (single detector) – Mean Value (all detectors). In the course of Temperature→Radiance →GVAR counts, no detector saturation is taken into account. Symbols used in the plots on this page and those following: + Detector 1* Detector 2◊ Detector 3∆ Detector 4  For channel 7 of both GOES-12 and GOES-13, detector 4 differs from the other three. GOES-12 GOES-13

Striping Due to SRF Difference (Channels 10 – 18)  For both GOES-12 and GOES-13, channels 11 and 12 have one detector behaving somehow differently from the other three. GOES-12 GOES-13

GVAR Counts Profiles of GOES-13 Sounder CH 1 – 9 During the ITT’s pre-launch spacecraft T/V tests, the Sounder was directed to view a target, whose temperature was controlled at 295 K. The T/V tests were recorded on a tape, which was played back and processed by the GOES SPS. The above profiles are organized channel by channel. Line types used for each channel are solid: Detector 1Dotted: detector 2dashed: Detector 3dash dotted: Detector 4 (cont’d)

GVAR Counts Profiles of GOES-13 Sounder CH 10 – 18  Channels 1 - 3, and 12 are saturated.  Channels 7 – 9, 11, and 13 – 15 appear to have one detector whose GVAR count profile is different from the other three.  For GOES-13 Channel 7, in particular, detector 4 seems to stand alone. This is consistent with the spectral response function profiles for the channel. In the GOES-13 NOAA Science Tests, however, the reported detector is detector 3.

Temperature Differences of GOES-13 Sounder CH 1 – 18 Temperature differences observed for each channel of GOES-13 Sounder during the ITT’s pre-launch spacecraft T/V tests.

GOES-13 Sounder Mean and Standard Deviation of Retrieved Temperatures over a Controlled Target Mean STD e e e e e e e e e e e e e e e e (Vertical: Channels; Horizontal: Detectors)