Thursday, November 10, 2022

The PO.DAAC is pleased to announce the release of the version 5.0 SMAP Sea Surface Salinity (SSS) data from Remote Sensing Systems (RSS).

The major changes in Version 5.0 from Version 4 are: (1) the addition of formal uncertainty estimates to all salinity retrieval products and (2) sea-ice flagging and sea-ice side-lobe correction based on direct ingestion of AMSR-2 brightness temperature (TB) measurements. This is in contrast to Version 4 and earlier versions, in which the sea-ice correction was based on an external sea-ice concentration product. The use of AMSR-2 TB measurements in the SMAP Version 5 products allows for salinity retrievals closer to the sea-ice edge and aids in the detection of large icebergs near the Antarctic.

This release includes level 2C and L3 mapped monthly and 8-day running mean SMAP-SSS. All products are in the netCDF4 file format and are CF/ACDD metadata standards compliant. Similar to prior releases, the 40-km and 70-km fields have been consolidated as variables within a single data product rather than being made available as distinct datasets. The 70-km data are based on a smoothing of the 40-km product, which is retrieved directly from the geophysical model function (Meissner et al. 2018). The 70-km version should be considered the official product with the 40-km included for experimental purposes. For most open ocean applications, the 70-km fields are the best used since they have significantly lower noise than the 40-km data. Please note that no SMAP salinity data are available from 08/09/2022 – 10/06/2022, as SMAP was not in science mode or flying in its nominal orbit during that time.

The RSS SMAP-SSS V5.0 datasets and the associated technical documentation are described, discoverable, and accessible via the PO.DAAC data portal. General information regarding the SMAP mission is available from the mission website and also via PO.DAAC’s SMAP and salinity webpages.





Download data using the PODAAC Data Subscriber:

  1. Source code:
  2. Example code:

podaac-data-subscriber -c SMAP_RSS_L3_SSS_SMI_MONTHLY_V5 -d myData -sd 2018-08-01T00:00:00Z -ed 2018-09-01T00:46:02Z


Meissner, T., F. J. Wentz, A. Manaster, R. Lindsley, 2022: Remote Sensing Systems SMAP Ocean Surface Salinities [Level 2C, Level 3 Running 8-day, Level 3 Monthly], Version 5.0 validated release. Remote Sensing Systems, Santa Rosa, CA, USA. Available online at, doi: 10.5067/SMP50-2SOCS , 10.5067/SMP50-3SPCS , 10.5067/SMP50-3SMCS


Sea Surface Salinity from SMAP RSS Level 3 V5 (2015-2022)


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.

Comments/Questions? Please contact or visit the PO.DAAC Ocean Wind Forum.