SMAP Salinity V3 Validated Release

Date Added: 
Tuesday, October 30, 2018

SMAP Salinity V3 Validated Release

SMAP sea surface salinity (SSS) V3.0 validated data are available from Remote Sensing Systems. The near-polar orbit of SMAP allows for complete global coverage of the oceans in 3 days with a repeat cycle of 8 days. The SMAP SSS V3.0 validated release contains 4 products:

  • Level 2C swath data
  • Level 3 8-day running averages
  • Level 3 monthly averages
  • Level 3 monthly (RF) rain-filtered averages

All products are provided at two spatial resolutions: 40-km and 70-km. For most open ocean applications, the 70-km products are the best to use as they have significantly lower noise.

All files are in netCDF4 format and are CF/ACDD compliant.

Full documentation here:

Major updates in this release:

  1. Use of Version 4 L1B SMAP RFI filtered antenna temperatures.
  2. Implementation of the geophysical model function from Aquarius Version 5 adapted to SMAP (Meissner et al. 2018).
  3. Use of the near real time CCMP wind speed and direction data as ancillary input.
  4. Inclusion of IMERG rain rate for the atmospheric liquid cloud water correction and rain flagging.
  5. Improved computation of antenna weighted land fraction (gland) and enhanced correction for land radiation intrusion from antenna sidelobes.
  6. Improved correction for emissive SMAP mesh antenna.
  7. An error in the computation of the gain-weighted sea ice fraction (gice) during 2017 and 2018 in V2.0 has been corrected.
  8. The salty biases at low latitudes and the fresh biases at high N latitudes that were observed in the V2.0 release, have disappeared or are much reduced in V3.0.

Known Issues

  1. A significant degradation in performance is observed during the early months of the SMAP mission (APR 2015 – AUG 2015). It might be related to instrument calibration, but its cause is currently unknown and needs further investigation.
  2. A significant degradation in performance is observed if the gain weighted land fraction (gland) exceeds 1%. Consequently, observations with gland>0.8% are not used in the Level 3 processing.


Meissner, T., F.J. Wentz, and D.M. Le Vine, 2018, The Salinity Retrieval Algorithms for the NASA Aquarius Version 5 and SMAP Version 3 Releases, Remote Sensing 10, 1121, doi:10.3390/rs10071121.

How to cite the RSS SMAP Salinity Data

As a condition of using these data, we require you to use the following citation:
Meissner, T., F. J. Wentz, A. Manaster, 2018: Remote Sensing Systems SMAP Ocean Surface Salinities [Level 2C, Level 3 Running 8-day, Level 3 Monthly], Version 3.0 validated release. Remote Sensing Systems, Santa Rosa, CA, USA. Available online at, doi: 10.5067/SSSSS-TTTTT.

In the doi, the string SSSSS is:

  1. SMP30 for the 40km resolution products
  2. SMP3A for the 70km resolution products.

and the string is TTTTT is:

  1. 2SOCS for the L2C files.
  2. 3SPCS for the L3 8-day running maps.
  3. 3SMCS for the L3 monthly maps and monthly RF maps.

Continued production of this data set requires support from NASA. We need you to be sure to cite these data when used in your publications so that we can demonstrate the value of this data set to the scientific community. Please include the following statement in the acknowledgement section of your paper:

"SMAP salinity data are produced by Remote Sensing Systems and sponsored by the NASA Ocean Salinity Science Team. Data are available at"