GOES-13 Sounder Filter Wheel Anomalies
On June 20, 2012, the GOES-13 Sounder Filter Wheel mechanism suffered an anomaly. The filter wheel moves the spectral filters into the optical path of sensed radiation. As a result of the anomaly, data quality was degraded starting at about 1248 UTC. Instrument recovery activities occurred at 1756 UTC on 20 June, and qualitatively the data returned to normal. Imager data were not affected.
When GOES Sounder data are degraded, GOES Sounder Derived Product Imagery is also degraded. For example, the Precipitable Water image from 1746 UTC on June 20 is shown above. GOES-15 Sounder data returns over the western United States do not show the data dropouts characterized by the Filter Wheel Anomalies in GOES-13 over the eastern United States.
Filter Wheel anomalies have occurred in the past on GOES-12. GOES-10 Filter Wheel anomalies caused a data interruption on GOES-10 from Oct 14th to Nov 6th, 2008. GOES-8 also suffered from rare filter wheel anomaly issues (Link).