RSS has completed an initial investigation and corrected a problem affecting SSMIS F17.
Beginning April 7, 2016, F17 began exhibiting anomalous behavior in the receiver gain for the 37GHz vertically polarized channel (37V). While gain shifts are normal, the 37V gain began jumping around far more often and significantly than usual.
Automated data quality checks at RSS initially discarded up to 50% of ocean product data due to excessive gain changes. After careful analysis, we have improved the quality check which now removes no more than 5% of data on the most affected days.
Additionally, the 37V gain change behavior seems to have stopped on May 20, 2016.
The problem appears to be limited to 37V, and more than 95% of the data in this time range can be corrected and used for a variety of purposes.
37V is a primary tool in measuring a variety of environmental data, including ocean winds, water vapor, clouds, rain and sea ice. Hindsight may reveal whether F17 remains a climate quality sensor, but initial correction results are promising.
Data downloaded before June 23rd 2016, had more missing data than necessary between March 1st and June 23rd. We recommend redownloading the corrected data files from our FTP server.