Aquarius Level 3 ancillary sea surface temperature (SST) standard mapped image data are the ancillary SST data used in the Aquarius calibration for salinity retrieval. They are simply the daily SSTs from the Reynolds National Climatic Data Center (NCDC) 0.25 degree GHRSST dataset, gridded and averaged using the Aquarius processing L2-L3 processing scheme to the same 1 degree spatial resolution and daily, 7 day, monthly, seasonal, and annual time intervals as Aquarius L3 standard salinity and wind speed products. This particular data set is the 7-Day, descending ancillary sea surface temperature product associated with version 3.0 of the Aquarius data set, which is the second official public data release from AQUARIUS/SAC-D mission.