Data for new versions of SPL2SMAP_S Level-1, -2, and -3 data sets are currently available from 27 August 2020 onward. Data since 31 March 2015 will become available as they are reprocessed.
Data Set ID: 
SPL2SMAP_S

SMAP/Sentinel-1 L2 Radiometer/Radar 30-Second Scene 3 km EASE-Grid Soil Moisture, Version 3

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. Additional analyses of in situ soil moisture stations will be conducted over the next several months, which should move the data quality to the validated category.

This is the most recent version of these data.

Version Summary: 

Changes to this version include:
- An improved calibration methodology was applied to the SMAP Level-1B brightness temperatures.
- Revised the coefficients in the land surface temperature computation to be consistent with the SMAP Level-2 soil moisture passive enhanced product. The new coefficients are C=0.246, K=1.007 for AM passes and C=1.0, K=1.007 for PM passes.
- Changed the omega parameter of the tau-omega model for forest landcover classes (1-5) from 0.05 to 0.07.
- Uses a new high-resolution soil database (SoilGrid250m; Hengl et al., 2017).
- Uses bulk density to set the upper limit of the soil moisture retrievals. Previous versions used a fixed value of 0.65 m3/m3.
- Enhanced documentation on Data Flags in the User Guide to help data users to better understand and use the flags.
- Added a bit in the TB Disaggregation QC flag to indicate (1) the use of SMAP AM or PM data; and (2) the time difference (greater or less than 36 hours) between the SMAP and Sentinel observations overlap.
- Fixed the EASE_[row/column]_index_apm_[1km/3km] data fields to make them 0-based.
- Fixed the range beginning and ending time in the file metadata.

For the full major and minor version history, go to https://nsidc.org/data/smap/data_versions.

COMPREHENSIVE Level of Service

Data: Data integrity and usability verified; data customization services available for select data

Documentation: Key metadata and comprehensive user guide available

User Support: Assistance with data access and usage; guidance on use of data in tools and data customization services

See All Level of Service Details

Parameter(s):
  • MICROWAVE > BRIGHTNESS TEMPERATURE
  • RADAR > SIGMA NAUGHT
  • SOILS > SOIL MOISTURE/WATER CONTENT > SURFACE SOIL MOISTURE
Data Format(s):
  • HDF5
Spatial Coverage:
N: 60, 
S: -60, 
E: 180, 
W: -180
Platform(s):SENTINEL-1A, SENTINEL-1B, SMAP
Spatial Resolution:
  • 3 km x 3 km
Sensor(s):C-SAR, SMAP L-BAND RADIOMETER
Temporal Coverage:
  • 31 March 2015
Version(s):V3
Temporal Resolution30 secondMetadata XML:View Metadata Record
Data Contributor(s):Das, N., D. Entekhabi, R. S. Dunbar, S. Kim, S. Yueh, A. Colliander, P. E. O'Neill, T. Jackson, T. Jagdhuber, F. Chen, W. T. Crow, J. Walker, A. Berg, D. Bosch, T. Caldwell, and M. Cosh.

Geographic Coverage

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As a condition of using these data, you must cite the use of this data set using the following citation. For more information, see our Use and Copyright Web page.

Das, N., D. Entekhabi, R. S. Dunbar, S. Kim, S. Yueh, A. Colliander, P. E. O'Neill, T. Jackson, T. Jagdhuber, F. Chen, W. T. Crow, J. Walker, A. Berg, D. Bosch, T. Caldwell, and M. Cosh. 2020. SMAP/Sentinel-1 L2 Radiometer/Radar 30-Second Scene 3 km EASE-Grid Soil Moisture, Version 3. [Indicate subset used]. Boulder, Colorado USA. NASA National Snow and Ice Data Center Distributed Active Archive Center. doi: https://doi.org/10.5067/ASB0EQO2LYJV. [Date Accessed].

Literature Citation

As a condition of using these data, we request that you acknowledge the author(s) of this data set by referencing the following peer-reviewed publication.

  • Das, N., D. Entekhabi, S. Dunbar, J. Chaubell, A. Colliander, S. Yueh, T. Jagdhuber, F. Chen, W. T. Crow, P. E. O'Neill, J. Walker, A. Berg, D. Bosch, T. Caldwell, M. Cosh, C. Holifield -Collins, E. Lopez-Baeza, and M. Thibeault. 2019. The SMAP and Copernicus Sentinel 1A/B microwave active-passive high resolution surface soil moisture product, Remote Sensing of Environment. 233. 111380. https://doi.org/10.1016/j.rse.2019.111380

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FAQ

What data subsetting, reformatting, and reprojection services are available for SMAP data?
The following table describes the data subsetting, reformatting, and reprojection services that are currently available for SMAP data via the NASA Earthdata Search, a Data Subscription, and Programmatic Access. Short name Title Subsetting Reformatting... read more

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Visualize NSIDC data as WMS layers with ArcGIS and Google Earth
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Search, order, and customize NSIDC DAAC data with NASA Earthdata Search
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Filter and order from a data set web page
Many NSIDC data set web pages provide the ability to search and filter data with spatial and temporal contstraints using a map-based interface. This article outlines how to order NSIDC DAAC data using advanced searching and filtering.  Step 1: Go to a data set web page This article will use the... read more
How do I convert an HDF5/HDF-EOS5 file into binary format?
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. Full instructions for installing and using h5dump on Mac/Unix and... read more
Read and plot SMAP/Sentinel-1 data with Matlab
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. These flags are useful for determining the overall... read more
Visualize and download NSIDC DAAC data with NASA Worldview
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NSIDC DAAC Data Subscription Requests
Data subscriptions are available for select NSIDC DAAC data collections (found below). Our subscription service automatically sends you new data as they are delivered from active NASA satellite missions. The service cannot be applied to past data already archived at NSIDC. This service is... read more