JPL SMAP Level 3 CAP Sea Surface Salinity Standard Mapped Image Monthly Validated, CAP Version 5.0

The PI-produced JPL V5.0 SMAP Sea Surface Salinity (SSS) and extreme winds Level 3 (L3) standard datasets is based on the JPL Combined Active-Passive (CAP) algorithm applied to data from the NASA Soil Moisture Active Passive (SMAP) observatory. For science applications, use of the standard products is strongly advised.

They also recommend the use of the V5.0 forward stream data over the prior version, which is deprecated and will be retired within the next 6 months. JPL SMAP V5.0 SSS is based on the newly released SMAP V5 Level-1 Brightness Temperatures (TB). An enhanced calibration methodology has been applied to the brightness temperatures, which improves absolute radiometric calibration and reduces the biases between ascending and descending passes. The improved SMAP TB Level 1 TB will enhance the use of SMAP Level-1 data for other applications, such as sea surface salinity and winds. Data begins on 1 April 2015 and is ongoing. Datasets comprising this release include the L2B orbital data and two L3 mapped, global coverage salinity datasets: an 8-day running mean dataset based on the repeat orbit of the SMAP mission, along with a monthly average dataset. The L3 data are gridded at 0.25 x 0.25. The spatial resolution of all four datasets is approximately 60 km.

The JPL SMAP-SSS CAP V5.0 datasets are described and discoverable via the PO.DAAC data portal.

Please note: The NASA Soil Moisture Active Passive (SMAP) observatory has entered a safe-mode starting from August 8, 2022 in order to maintain its essential functions but stops science data acquisition. The Project team is investigating the cause of the anomaly and actively working on resuming operations to restart science data acquisition. The PODAAC SMAP SSS datasets will not have science data products during this period.

The SMAP Algorithm Theoretical Basis Document (ATBD), validation analysis and file specification document together with other primary technical documentation are available from the podaac. General information regarding the SMAP mission is available from the mission website and also via PO.DAAC's SMAP and salinity webpages.

Reference:
Fore, A.G, S.H. Yueh, W. Tang, B.W. Stiles, and A.K. Hayashi (2016). Combined Active/Passive Retrievals of Ocean Vector Wind and Sea Surface Salinity With SMAP. IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING, VOL. 54, NO. 12. p.7396-7404. DOI: 10.1109/TGRS.2016.2601486

Citation:
Fore, A., S. Yueh, W. Tanh, A. Hayashi, 2020: JPL SMAP Ocean Surface Salinity Products [Level 2B, Level 3 Running 8-day, Level 3 Monthly], Version 5.0 validated release. Jet Propulsion Laboratory, Pasadena, CA, USA.

Documentation:
JPL SMAP-SSS CAP V5.0 ATBD Validation and Users Guide
SMAP-SSS Project and Instrument Overview
NASA SMAP Mission Website

Data outages and known Issues:

Comments/Questions? Please contact podaac@podaac.jpl.nasa.gov or visit the PO.DAAC Forum.

Variables
sea surface salinity (psu), reference sea surface salinity from hycom (psu), sea surface temperature (k), smap 10 m wind speed (m s-1), smap 10 m wind speed (using ancillary sss) (m s-1), sum of gaussian weighting factors, average ice fraction, average land fraction, smap sss uncertainty (1e-3)
Zonal Global by 0.25 deg
Meridional Global by 0.25 deg
Vertical Surface
Temporal Apr 2015 to near present by 1 month
Static?no
Volume ~7MB per month
Serverpublic:
Source SMAP-SSS Project and Instrument Overview
Acquired January 5, 2021
APDRC contact
Supplements JPL SMAP-SSS CAP V5.0 ATBD Validation and Users Guide