This circuit periodically applies an analog offset to the signals from the infrared detector to maintain the signals within the range of the Analog-to-Digital Converter. The January 19 anomaly disabled this automatic adjustment, leading to saturated signals on 1413 of the AIRS 2378 spectral channels. Following a reset of the DC-Restore on January 28th, standard AIRS science data product generation has resumed, and data quality has returned to nominal levels. The anomaly occurred coincident with a rollover in a signed 32‑bit seconds‑since‑epoch counter referenced to the TAI epoch, though the specific subsystem responsible for that counter has not yet been identified.
The AIRS L1B, V5 data collection is available for the anomalous period, starting January 19, granule 27 and extending to January 28, granule 231. The use of proper quality flags for screening data needs to be exercised before use. All granules in this period are affected by the DC-Restore anomaly.
The AIRS L2/L3 V7 data collection was not processed and will have a permanent gap during the anomalous period.