DQR ID | Subject | Data Streams Affected |
---|---|---|
D100218.2 | SGP/AERI/C1 - Fault within the channel 2 (InSb) detector | sgpaerich2C1.b1, sgpaeriprof3feltzC1.c1, sgpaeriprof3feltzC1.s1, sgpaerich2nf1turnC1.c1 |
Start Date | Start Time | End Date | End Time |
---|---|---|---|
09/10/2009 | 0000 | 03/02/2010 | 2359 |
Subject: | SGP/AERI/C1 - Fault within the channel 2 (InSb) detector |
DataStreams: | sgpaerich2C1.b1, sgpaeriprof3feltzC1.c1, sgpaeriprof3feltzC1.s1, sgpaerich2nf1turnC1.c1 |
Description: | On 10 Sep 2009, an "event" happened at the SGP site which impacted the AERI instrument. This event has been documented in DQPR 2258. This event had a tremendous impact on the radiance, and in particular the noise level, in the channel 2 data (which uses the InSb detector). After much effort by the site operators and mentors, it appeared that the system was "fixed" on 5 October 2009. However, there were some weird irregularities in the dataset that were bothersome, and necessitated a more complete analysis. We (the instrument mentor team) have concluded that the fault suffered on Sept 10 affected the grounding of the InSb detector. The symptoms included a 'wandering' of the phase of the interferogram, which results in errors in calibration, as well as increased noise in the data. We have attempted to correct the data for a few days by hand, as phase errors typically can be accounted for; however, in these cases we were unable to do this satisfactorily with significant amounts of atmospheric signal remaining in the imaginary spectrum and low-frequency biases remaining in the real spectrum. [If the data are properly calibrated, then the real spectrum is what is used for science and has all of the atmospheric signal, while the imaginary spectrum should be all random noise.] Therefore, we have concluded that all radiance data from the channel 2 detector of this system, including all downstream data products that make use of these data, should be classified as INCORRECT / BAD. The channel 1 data (which is from a different detector) appears to be fine and properly calibrated. The system will be replaced with the spare AERI. |
Measurements: | sgpaerich2nf1turnC1.c1:
sgpaerich2C1.b1:
sgpaeriprof3feltzC1.s1:
sgpaeriprof3feltzC1.c1:
|