The Physical Oceanography Distributed Active Archive Center (PO.DAAC) is pleased to announce the availability of new Level-2 and 3 datasets from the Combined Active-Passive (CAP) Algorithm applied to version 4.0 of the Aquarius/SAC-D data. CAP is a P.I. produced data set developed and provided by the JPL Climate Oceans and Solid Earth group. L3 datasets include both 7-day rolling average and monthly CAP sea surface salinity (SSS), rain corrected SSS and wind speed mapped products. The CAP algorithm simultaneously retrieves salinity, wind speed and wind direction by minimizing the sum of squared differences between model and observations. The main improvement in CAP V4.0 is calibration of the rain roughness correction geophysical model function to HYCOM SSS adjusted by the Rain Impact Model (RIM) to account for the rain induced near surface stratification. Rain corrected salinity retrieval at L2 is based on collocation with ancillary rain rate from NOAA CMORPH at 0.25 degree and 30 minute resolution, replacing the SSMI/S and WindSAT data previously used for this in CAP V3.0. Data are processed for the entire duration of the Aquarius/SAC-D mission: 8/26/2011 – 6/7/2015. All users are encouraged to work with v4.0 over any prior CAP versions.
The V4.0 CAP data sets are described and discoverable via the PO.DAAC data portal. Access to these data is
via PO.DAAC’s public FTP site (ftp://podaac-ftp.jpl.nasa.gov/allData/aquarius/L2/CAPv4/
and ftp://podaac-ftp.jpl.nasa.gov/allData/aquarius/L3/mapped/CAPv4/)
and also via OPeNDAP, and THREDDS.
L3 CAP data set visualization and subsetting will in future be available via
LAS.
The CAP
V4.0 ATBD & Users Guide , which includes also a description of
improvements over prior versions and an assessment of CAP V4.0 data accuracy,
is available from the FTP site together with other primary technical documentation relating to these data and associated
reader software. General information
regarding Aquarius/SAC-D mission is available from the mission website and also
via PO.DAAC’s Aquarius and salinity webpages.
Questions may be addressed to: podaac@podaac.jpl.nasa.gov