SMAP Sea Surface Salinity Monthly Maps from NASA JPL

April 2015 onward monthly global sea surface salinity data from NASA's Soil Moisture Active Passive (SMAP) satellite. The JPL-produced Level 3 product uses a Combined Active-Passive algorithm and is gridded at 0.25-degree resolution with an approximate spatial resolution of 60km. It includes derived salinity with uncertainties, wind speed, and ancillary surface salinity from HYCOM.

Use Cases

• Monitoring global ocean salinity trends based on monthly mapped sea surface salinity data.
• Assessing satellite retrieval algorithm performance based on derived SSS with associated uncertainties.
• Correlating sea surface salinity with wind patterns based on included SMAP wind speed data.
• Validating and complementing hydrodynamic model outputs based on ancillary surface salinity from HYCOM.

Strengths

• Data begins April 1, 2015 and is ongoing, providing a multi-year time series.
• Global coverage gridded at 0.25-degree x 0.25-degree resolution.
• Based on an enhanced calibration methodology for brightness temperatures, improving radiometric calibration.
• Integrates complementary active and passive sensing from SMAP's L-band radiometer and radar.

Limitations

• Description metadata is limited; actual data quality requires manual inspection after download.
• Column-level documentation is absent; field semantics must be inferred after download.
• A malfunction of the SMAP scatterometer on 7 July affected the surface roughness correction required for salinity retrieval.

Provenance

Source

National Aeronautics and Space Administration (NASA), Jet Propulsion Laboratory (JPL)

Collection Method

Satellite remote sensing from the SMAP observatory using the Combined Active-Passive (CAP) retrieval algorithm.

Time Range

April 2015 onward

Freshness

Processing latency is 1 month; last metadata update was 2026-03-13.

Geography

Global