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Level 1B
Instrument Performance History
Channel to channel non-uniform response functions within a band
Description | L1B Impact | L2 Impact | Cause | Mitigation | Schedule | History
DESCRIPTION:
This effect appears in the MWIR thermal
bands (Bands 20 - 25). It is seen as along track striping within a
scene. [VERIFY: It appears less prominently in the LWIR PV bands (27 – 30)]
Illustration of effect
IMPACT TO L1B DATA SET:
Non-uniform channel to channel response of 0.5% to 1.0% in radiance has been reported.
ESTIMATED IMPACT TO L2 SCIENCE PRODUCTS:
The effect could introduce errors or uncertainties of up of 2 degrees Celsius in a 4-µm based Sea-Surface Temperature product.
CAUSE OF EFFECT:
The effect is due to the use of a linear
calibration for these bands in the initial version of the algorithm,
when the actual functioning of the detectors is non-linear (quadratic).
Slight variations in the non-linear behavior of one detector to another
will lead to an apparent striping in the radiance product for temperatures
different than the temperature of the OBC-BB.
This situation is the result of the pre-launch electronics change for
electronic cross-talk.
MITIGATION APPROACH/ADDED TESTING TO CHARACTERIZE EFFECT:
On-orbit observations of an OBC-BB over the temperature range 274 K to 315 K enabled a determination of these non-linear terms, and these values were installed with the LUT update known as the St. Patrick’s Day update, beginning on 17 March 2000.
ESTIMATED SCHEDULE TO COMPLETE:
Completed.
HISTORY OF CHARACTERISTIC:
| Epoch Number |
Time Span | Version Number at start of epoch |
General Characteristics | Improvements | Documentation |
|---|---|---|---|---|---|
| 1 | Feb. 24, 2000 - March 16, 2000 2000055.1550 - 2000076.2122 |
2.3.2.0 | Imprecise calibration due to use of pre-launch gains. | ||
| 2 | March 16, 2000 - present 2000076.2122 - present |
2.3.2.3 | Updated gains from on-orbit study fixes the problem. | MCST library document M0973 |
Description | L1B Impact | L2 Impact | Cause | Mitigation | Schedule | History
Please contact Jack Xiong with any technical questions concerning these pages.
Responsible Civil Servant:
Dr. Jack Xiong <Xiaoxiong.Xiong.1@gsfc.nasa.gov>
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Last Update: July 1, 2008