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Description
This enhanced Level-3 (L3) soil moisture product provides a composite of daily estimates of global land surface conditions retrieved by the Soil Moisture Active Passive (SMAP) radiometer. This product is a daily composite of SMAP Level-2 (L2) soil moisture which is derived from SMAP Level-1C (L1C) interpolated brightness temperatures. Backus-Gilbert optimal interpolation techniques are used to extract information from SMAP antenna temperatures and convert them to brightness temperatures, which are posted to the 9 km Equal-Area Scalable Earth Grid, Version 2.0 (EASE-Grid 2.0) in a global cylindrical projection.
Version Description
Changes to this version include:
As part of the algorithm changes, the following data fields were added: bulk_density, clay_fraction.
The baseline algorithm (SCA-V) remains unchanged.
Improved aggregation of values in input ancillary data, e.g. roughness, soil texture, NDVI. The fix has negligible impacts on retrievals estimated to be of recommended quality.
Citation is critically important for dataset documentation and discovery. This dataset is openly shared, without restriction, in accordance with the EOSDIS Data Use and Citation Guidance.
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ONeill, P., Chan, S., Njoku, E., Jackson, T., Bindlish, R., & Chaubell, J. (2019). SMAP Enhanced L3 Radiometer Global Daily 9 km EASE-Grid Soil Moisture, Version 3 [Dataset]. NASA National Snow and Ice Data Center Distributed Active Archive Center. https://doi.org/10.5067/T90W6VRLCBHI Date Accessed: 2026-10-27
@misc{oneill_chan_njoku_jackson_bindlish_chaubell_2019,
title={SMAP Enhanced L3 Radiometer Global Daily 9 km EASE-Grid Soil Moisture, Version 3},
url={http://nsidc.org/data/SPL3SMP_E/versions/3},
DOI={10.5067/T90W6VRLCBHI},
publisher={NASA National Snow and Ice Data Center Distributed Active Archive Center},
author={ONeill, Peggy and Chan, Steven and Njoku, Eni and Jackson, Thomas and Bindlish, Rajat and Chaubell, Julian},
year={2019},
}
ONeill, P., Chan, S., Njoku, E., Jackson, T., Bindlish, R., & Chaubell, J. (2019). SMAP Enhanced L3 Radiometer Global Daily 9 km EASE-Grid Soil Moisture, Version 3 [Dataset]. NASA National Snow and Ice Data Center Distributed Active Archive Center. https://doi.org/10.5067/T90W6VRLCBHI Date Accessed: 2026-10-27
ONeill, Peggy, et al. “SMAP Enhanced L3 Radiometer Global Daily 9 Km EASE-Grid Soil Moisture, Version 3.” NASA National Snow and Ice Data Center Distributed Active Archive Center, 2019, https://doi.org/10.5067/T90W6VRLCBHI. Date Accessed: 2026-10-27
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