JPL's SMAP V5.0 dataset provides monthly global maps of sea surface salinity derived from L-band radiometer and radar data. Data spans from April 2015 to the present, gridded at a 0.25-degree resolution with an approximate 60km spatial scale. The product is produced by NASA's Jet Propulsion Laboratory using the Combined Active-Passive retrieval algorithm.
Use Cases
- Analyzing long-term trends in sea surface salinity (SSS) to study ocean freshening or salinification patterns.
- Validating ocean circulation models by comparing modeled salinity fields against the derived SSS and ancillary HYCOM surface salinity data.
- Investigating the impact of wind speed, a provided variable from SMAP, on sea surface salinity variability and mixing.
- Assessing retrieval algorithm performance by examining the associated uncertainty fields for each salinity measurement.
- Studying the spatial coherence of salinity features using the global 0.25-degree gridded data product.
Strengths
- Global spatial coverage at a consistent 0.25-degree x 0.25-degree grid resolution.
- Temporal coverage from April 2015 onward provides a multi-year record for climate studies.
- Data incorporates an enhanced calibration methodology for brightness temperatures, improving radiometric accuracy.
- Product includes derived sea surface salinity alongside associated uncertainty estimates and ancillary wind speed data.
Limitations
- Spatial resolution is approximately 60km, which may be too coarse for studying small-scale ocean features.
- A scatterometer malfunction on July 7, 2015, affected surface roughness correction, potentially impacting salinity retrievals from that period.
- The dataset has a stated processing latency of one month, preventing real-time analysis.
Provenance
- Source
- NASA Soil Moisture Active Passive (SMAP) observatory, processed by the Jet Propulsion Laboratory.
- Collection Method
- Derived from SMAP Level-1 Brightness Temperatures using the JPL Combined Active-Passive (CAP) retrieval algorithm.
- Time Range
- April 2015 to present (ongoing).
- Freshness
- Monthly updates with a 1-month latency. Data collection is ongoing.
- Geography
- Global extent.