NASA SMAP Project: Soil Moisture and Freeze/Thaw Data from Satellite Radiometer

NASA's Soil Moisture Active Passive (SMAP) mission provides calibrated brightness temperatures and derived soil moisture and landscape freeze/thaw data. The dataset includes enhanced Level-1C, Level-2, and Level-3 products posted to a 9 km EASE-Grid 2.0, collected during 6:00 a.m. descending and 6:00 p.m. ascending half-orbit passes. Data were also collected during four validation campaigns: SGP99, CLASIC07, SMEX02, and SMAPVEX08.

Use Cases

• Retrieving surface soil moisture based on 9-km gridded brightness temperatures.
• Analyzing daily global landscape freeze/thaw conditions based on Level-3 composite data.
• Validating soil moisture models using campaign data from SGP99, CLASIC07, SMEX02, and SMAPVEX08.
• Studying land surface interactions using calibrated, geolocated brightness temperatures from ascending and descending passes.

Strengths

• Data is processed using Backus-Gilbert optimal interpolation techniques for enhanced information extraction.
• Products are posted to a standardized 9 km Earth-fixed grid (EASE-Grid 2.0) in multiple map projections.
• Includes data from four dedicated soil moisture validation campaigns spanning from 1999 to 2008.

Limitations

• Column-level documentation is absent; field semantics must be inferred after download.
• Row count and total dataset size are unknown, which may limit suitability assessment.
• Last update date is unknown; freshness unverified.

Provenance

Source

NASA Soil Moisture Active Passive (SMAP) mission.

Collection Method

Data acquired by the SMAP radiometer and processed through Level-1C, Level-2, and Level-3 pipelines.

Time Range

Campaign data from 1999, 2002, 2007, and 2008. SMAP satellite operational timeframe not specified.

Freshness

As of 2021, data were also posted to the Northern Hemisphere EASE-Grid 2.0. Last updated date is unknown.

Geography

Global coverage, with specific campaigns in the Southern Great Plains and other regions.