Alaska Satellite Facility - Distributed Active Archive Center

Soil Moisture Active Passive (SMAP) Mission


The SMAP mission objective is to provide global measurements of soil moisture and its freeze-thaw state. SMAP measures the amount of water in the top 5 cm (2 inches) of soil everywhere on the Earth’s surface every three days. These data are useful for:

  • Further understanding of processes that link the water, energy, and carbon cycles
  • Enhance weather and climate prediction models
  • Quantify net carbon flux in boreal landscapes
  • Develop improved flood-prediction and drought-monitoring capabilities

The SMAP spacecraft instrumentation features an L-band radiometer and L-band synthetic aperture radar (SAR), measuring surface emissions and backscatter and sensing soil conditions through moderate vegetation cover.

Level-1 SAR data products from the SMAP mission are available through the Alaska Satellite Facility DAAC. Level-1 through Level-4 radiometer data and Level-2 and Level-3 radar data are available from the National Snow and Ice Data Center DAAC. In 2015, a failure of the radar power supply caused the SAR sensor to stop operating. Therefore, active SAR data are only available for April 13 – July 7, 2015. More information on the anomaly is available from JPL.

Jet Propulsion Laboratory