N: 85.044 S: -85.044 E: 180 W: -180
TABLE OF CONTENTS
Description
This Level-2 (L2) soil moisture product provides estimates of global land surface conditions retrieved by the Soil Moisture Active Passive (SMAP) passive microwave radiometer during 6:00 a.m. descending and 6:00 p.m. ascending half-orbit passes. SMAP L-band brightness temperatures are used to derive soil moisture data, which are then resampled to an Earth-fixed, global cylindrical 36 km Equal-Area Scalable Earth Grid, Version 2.0 (EASE-Grid 2.0).
Version Description
Changes to this version include: (1) Level-1B water-corrected brightness temperatures are used in passive soil moisture retrieval. This procedure corrects for anomalous soil moisture values seen near coastlines in the previous version and should result in less rejected data due to waterbody contamination. Five new data fields accommodate this correction: grid_surface_status, surface_water_fraction_mb_h, surface_water_fraction_mb_v, tb_h_uncorrected, and tb_v_uncorrected. (2) Improved depth correction for effective soil temperature used in passive soil moisture retrieval; new results are captured in the surface_temperature data field. This correction reduces the dry bias seen when comparing SMAP data to in situ data from the core validation sites. (3) Frozen ground flag updated to reflect improved freeze/thaw detection algorithm, providing better accuracy; new results are captured in bit 7 of the surface_flag.
Product Summary
Platforms
Instruments
Spatial Extent
Spatial Resolution
36 Kilometers x 36 Kilometers
Spatial Reference System(s)
WGS 84 / NSIDC EASE-Grid 2.0 Global (EPSG:6933)
Location
GLOBAL LAND
Coordinate System
CARTESIAN
Granule Spatial Representation
GEODETIC
Temporal Extent
2015-03-31 to 2019-08-13
Temporal Resolution
49 Minute
Concept ID
C4100780583-NSIDC_CPRD
Data State
DEPRECATED
Number of Files/Granules
0
Processing Level
2
Published
Updated
Science Keywords
Brightness Temperature
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Citation
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. (2018). SMAP L2 Radiometer Half-Orbit 36 km EASE-Grid Soil Moisture, Version 5 [Data set]. NASA National Snow and Ice Data Center Distributed Active Archive Center. https://doi.org/10.5067/SODMLCE6LGLL Date Accessed: 2026-05-16
ONeill, Peggy, Steven Chan, Eni Njoku, Thomas Jackson, and Rajat Bindlish. “SMAP L2 Radiometer Half-Orbit 36 Km EASE-Grid Soil Moisture, Version 5.” NASA National Snow and Ice Data Center Distributed Active Archive Center, 2018. doi:10.5067/SODMLCE6LGLL. Date Accessed: 2026-05-16
ONeill, Peggy, et al. SMAP L2 Radiometer Half-Orbit 36 Km EASE-Grid Soil Moisture, Version 5. NASA National Snow and Ice Data Center Distributed Active Archive Center, 2018, doi:10.5067/SODMLCE6LGLL. Date Accessed: 2026-05-16
TABLE OF CONTENTS