Starting on 25 April 2015 (orbital rev 3333) and continuing to present
day, the ISS spacecraft experienced changes in attitude in excess of the
nominal spacecraft attitude for RapidScat wind retrieval in comparison to the
previous portion of the mission. This presented issues with the quality of
the data which prompted the RapidScat Project to issue a quarantine on all
data files starting with orbital rev 3333 (25 April 2015) through 4157 (17
June 2015).
For a more thorough review of the data quality disruption which resulted in
the data quarantine, please review the previous PO.DAAC announcement here:
http://podaac.jpl.nasa.gov/announcements/2015-06-19_RapidScat_L2B_Data_Quality_Disruption
The RapidScat project has since reprocessed these data files with a series of
corrections summarized below:
- Invalid VV-pol fore pulses near the nadir track are now correctly flagged as invalid and not used in wind retrieval or quality flagging.
- Whole pulses are no longer flagged as invalid when any science slices in that pulse are not constrained to be on the surface of the Earth. This affected HH-aft observations near the nadir track.
- Adapted the rain-flagging to work in portions of the swath where one outer beam look is missing.
These corrections improve the wind retrieval accuracy and reduce the number
of rain-flagged data to the nominal percentage as well as enable the
RapidScat Project to rain-flag the portions of the swath where the VV-pol
fore pulses are missing.
All previously quarantined data files have been replaced with the
reprocessed, corrected versions and are now available for public access on
the PO.DAAC FTP and OPeNDAP sites.
The ISS spacecraft attitude anomaly is expected to persist through 23 July
2015.
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