SMOS Surface Soil Moisture

Available products

L3 Surface Soil Moisture

The Level 3 (L3) soil moisture products v3 are generated from applying a quality filtering and binning to the swath-based Level 2 (L2) soil moisture User Data Product (UDP) v650 from the European Space Agency (ESA). Ascending and descending orbits are processed separately.

Global surface soil moisture in ISEA 4H9 grid (15 km)

‘ This daily product corresponds to the temporal average of the L2 soil moisture measurements of all orbits within a day in the Icosahedral Snyder Equal Area (ISEA) grid, which is used by official ESA SMOS products.

Global surface soil moisture EASE-2  grid (25 km)

‘ These products correspond to the spatial average of the L2 soil moisture measurements in the Equal Area Scalable Earth (EASE)-2 grid of 25 km. They have different temporal averaging periods (and generation rates).

1-day map (daily)

3-days map (daily)

9-days maps (every 3 days)

1-monthly map (monthly)

1-year product (yearly)

L4 Surface Soil Moisture

The cloud-free Level 4 (L4) soil moisture products v5 at 1 km resolution are generated from applying a data fusion downscaling algorithm, which combines:

  •  the SMOS Level 1C (L1C) brightness temperature, provided by ESA and processed by BEC,
  •  the land surface temperature (LST) or skin temperature provided by the operational European Center for Medium Weather Forecast (ECMWF) model (, and
  • the Normalized Difference Vegetation Index (NDVI) from Terra Moderate Resolution Imaging Spectroradiometer (MODIS), distributed by the National Aeronautics and Space Administration (NASA,

The data fusion technique uses the BEC L3 soil moisture v3 as benchmark. An updated version of the downscaling algorithm employs a shape adaptive moving window to obtain daily high resolution soil moisture maps over any non-frozen region of the world, even if the region integrates different climates (Portal et al, 2018, JSTARS). Additionally, the integration of the modeled ECMWF LST in the algorithm allows estimating soil moisture, regardless of cloud cover. Ascending and descending orbits are processed separately.

Surface soil moisture at EASE-2 (1km)

1-day map (daily) over Europe

Related documents

Products description: BEC_SMOS-PD_SM_L3v3_L4v5.pdf