Sea Surface Salinity

Dataset Name Sensor Make Spatial Resolution Temporal Resolution Start Date End Date
Sea Surface Salinity sat Observation 70km x 70km Daily 2015-03-31 2019-04-21

Dataset Description

The Sea Surface Salinity dataset in CMAP is the SMAP_RSS_L3_SSS_SMI_8DAY-RUNNINGMEAN_V3_70KM_1 NASA dataset. This 8-day running mean sea surface salinity product has near-global spatial coverage gridded to ~ 70km x 70km grid cells. While a 40km x 40km product exists, the 70km product has a much higher SNR. The SSS data is derived from an L-band radiometer atop of the Soil Moisture Active Pass (SMAP) satellite mission. SMAP operates in a near-polar orbit with a beam swath of 1000km. Exact repeat overpasses happen every eight days, with near-global coverage every three days.

SSS data was referenced against the HYCOM reference salinity field. Multiple QA flags are described on page 38 of the [Technical Documentation](

NOTE Two known issues identified by that dataset distributor are:

  • Satellite retrieval performance was degraded between Apr. 2015 - Aug. 2015, possibly due to instrument calibration issues.
  • Eight of the total observations days were missing a sea-ice mask. To minimize contamination of salinity samples, these data were excluded from the Level-2 product, therefore some of the level-3 gridded products around these dates may have less total observations. The dates are: 12-03-2015, 12-03-2015, 04-15-2016, 04-16-2016, 09-27-2017, 09-28-2017, 11-25-2017 and 12-16-2018.

Table of Variables

How to Acknowledge

Meissner, T., F. Wentz, A. Manaster, 2018.Remote Sensing Systems SMAP L2C Sea Surface Salinity, Version 3.0 validated release, Remote Sensing Systems, Santa Rosa, CA, USA.

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

SMAP salinity are produced by Remote Sensing Systems and sponsored by NASA. Data are available at

Version History