• NSIDC DAAC is currently upgrading our data ingest process for NASA Earthdata Cloud. During this transition, users may notice temporary interruptions in data availability or notice small data gaps. All gaps will be resolved as quickly as possible. During this upgrade jpeg browse imagery will also not be available for preview in Earthdata search. Please reach out to NSIDC User Services with any questions or concerns.

  • On Wednesday, September 24 from 9:00 a.m. to 1:30 p.m. (US Mountain Time), this data set may not be available in the legacy data archive due to a planned system maintenance. Earthdata Cloud access will remain available for data sets that have migrated. Users of the SMAP near real-time products should use the NASA LANCE HTTPS File System for data access.

  • The NSIDC DAAC is retiring access to its legacy, on-premises data archive and transitioning to the NASA Earthdata Cloud as the primary data archive. View planned retirement dates here.

SMAP/Sentinel-1 L2 Radiometer/Radar 30-Second Scene 3 km EASE-Grid Soil Moisture, Version 2
Data set id:
SPL2SMAP_S
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 https://nsidc.org/data/smap/version-history
In this section
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Overview

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.
Parameter(s):
SOIL MOISTURE
Platform(s):
SENTINEL-1A
SENTINEL-1B
SMAP
Sensor(s):
C-SAR
SMAP L-BAND RADIOMETER
Data Format(s):
HDF5
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
    EPSG:6933
Spatial Coverage:
  • N:
    60
    S:
    -60
    E:
    180
    W:
    -180
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.

Documentation

Help Articles

General Questions & FAQs

FAQs About NSIDC DAAC's Earthdata Cloud Migration
This article covers frequently asked questions about the NASA NSIDC DAAC's Earthdata cloud migration project and what it means to data users.
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What data subsetting, reformatting, and reprojection services are available for SMAP data?
This short article describes the customization services available for SMAP data using Earthdata Search.
Read More
When will the legacy, on-premises archive be retired?
The NASA National Snow and Ice Data Center Distributed Active Archive Center (NSIDC DAAC) is migrating its primary data access from its legacy, on-premises archive to the NASA Earthdata Cloud.
Read More

How to Articles

Filter and order from a data set web page using the Data Access Tool
Many NSIDC DAAC data sets can be accessed using 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:
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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.
Read More
NASA Earthdata Cloud Data Access Guide
The NASA Earthdata Cloud is the NASA cloud-based archive of Earth observations. It is hosted by Amazon Web Services (AWS). Learn how to find and access NSIDC DAAC data directly in the cloud.
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.
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Search, order, and customize NSIDC DAAC data with NASA Earthdata Search
This article highlights the NSIDC DAAC data sets available with customization options and outlines a workflow for searching, ordering, and customizing data in NASA Earthdata Search. This approach is ideal for users who want to download data to their local machine.
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Visualize and download NSIDC DAAC data with NASA Worldview
NASA Worldview is a map interface that allows users to interactively browse imagery, create visualizations, and download the underlying data.
Read More
Visualize NSIDC data as WMS layers with ArcGIS and Google Earth
NASA's Global Imagery Browse Services (GIBS) provides up to date, full resolution imagery for selected NSIDC DAAC data sets. 
Read More