SMAP/Sentinel-1 L2 Radiometer/Radar 30-Second Scene 3 km EASE-Grid Soil Moisture, Version 2
Data set id:
DOI: 10.5067/KE1CSVXMI95Y
There is a more recent version of these data.
Version Summary

Changes to this version include:

  • Implemented a new method of identifying and eliminating spurious sigma0 values in Sentinel-1A/B Level-1 sigma0 data using a hybrid approach that combines a median filter with thresholding. As a result, fewer spurious sigma0 values (mainly due to small man-made structures) bias the aggregated 1 km data.

  • Replaced the previous 3 km resolution urban fraction map with a new 1 km map.

  • Adjusted the thresholds used with the new 1 km urban fraction map to: 0.25 (no flag), 0.25 – 0.5 (flagged, retrieval performed), and 0.5 (masked, no retrieval). These are provided in bit 3 of the surface_flag data field.

  • Adjusted the tau-omega parameters to be consistent with the values used in SPL2SMP/SPL2SMP_E algorithm.

  • Implemented minor bug fix to the SMAP and Sentinel-1 overlap computation code.

For the full major and minor version history, go to


This Level-2 (L2) soil moisture product provides estimates of land surface conditions retrieved by both the Soil Moisture Active Passive (SMAP) radiometer during 6:00 a.m. descending and 6:00 p.m. ascending half-orbit passes and the Sentinel-1A and -1B radar. SMAP L-band brightness temperatures and Copernicus Sentinel-1 C-band backscatter coefficients are used to derive soil moisture data, which are then resampled to an Earth-fixed, cylindrical 3 km Equal-Area Scalable Earth Grid, Version 2.0 (EASE-Grid 2.0).Note: These data are Beta-release quality, meaning that they have not undergone full validation and may still contain significant errors.
Data Format(s):
Temporal Coverage:
31 March 2015 to 26 August 2020
Temporal Resolution:
  • 30 second
Spatial Resolution:
  • 3 km
  • 3 km
Spatial Reference System(s):
WGS 84 / NSIDC EASE-Grid 2.0 Global
Spatial Coverage:
Blue outlined yellow areas on the map below indicate the spatial coverage for this data set.

Data Access & Tools

This data set has been retired. There is a more recent version of these data.

Help Articles

General Questions & FAQs

This short article describes the customization services available for SMAP data using Earthdata Search.

How to Articles

Many NSIDC DAAC data sets can be accessed using the NSIDC DAAC's Data Access Tool. This tool provides the ability to search and filter data with spatial and temporal constraints using a map-based interface.Users have the option to
To convert HDF5 files into binary format you will need to use the h5dump utility, which is part of the HDF5 distribution available from the HDF Group. How you install HDF5 depends on your operating system.
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This articles provides an example MATLAB snippet to read and plot SMAP/Sentinel-1 L2 Radiometer/Radar 30-Second Scene 3 km EASE-Grid Soil Moisture HDF5 soil moisture and brightness temperature data, as well as the related surface and quality flags.
NASA Earthdata Search is a map-based interface where a user can search for Earth science data, filter results based on spatial and temporal constraints, and order data with customizations including re-formatting, re-projecting, and spatial and parameter subsetting.
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