PO.DAAC announced the availability of the Level 4 optimally interpolated, 0.5 degree, near-global, 7-day sea surface salinity (OISSS) product for version 5.0 of the Aquarius/SAC-D dataset.  OISSS is a principal investigator produced dataset developed at the International Pacific Research Center (IPRC) of the University of Hawaii at Manoa, School of Ocean and Earth Science and Technology (SOEST).  The optimal interpolation (OI) mapping procedure used to create this product corrects for systematic spatial biases in Aquarius SSS data with respect to in-situ near-surface salinity observations and takes into account available statistical information about the signal and noise, specific to the Aquarius instrument. 

See entire announcement at: https://podaac.jpl.nasa.gov/announcements/2018-07-27_IPRC_SOEST_OISSS_Aq...