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Description

This enhanced Level-2 (L2) product contains calibrated, geolocated, brightness temperatures acquired by the Soil Moisture Active Passive (SMAP) radiometer during 6:00 a.m. descending and 6:00 p.m. ascending half-orbit passes. This product is derived from SMAP Level-1B (L1B) interpolated antenna temperatures. Backus-Gilbert optimal interpolation techniques are used to extract maximum 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 [available as the SPl1CTB_E product]. As of 2021, the data are also posted to the Northern Hemisphere EASE-Grid 2.0, an azimuthal equal-area projection. These 9-km brightness temperatures are then used to retrieve surface soil moisture posted on the 9-km grid [this SPL2SMP_E product].

Version Description

Changes to this version include: • An improved processing methodology was applied to the input enhanced Level-1C radiometer brightness temperatures • The data algorithms, structure, content, or processor code are otherwise unchanged from the previous version For the full major and minor version history, go to https://nsidc.org/data/smap/version-history

Product Summary

Platforms
SMAP
Instruments
SMAP L-BAND RADIOMETER
Spatial Extent

N: 90 S: -85.044 E: 180 W: -180

Spatial Resolution
9 Kilometers x 9 Kilometers
Location
GLOBAL LAND ,
NORTHERN HEMISPHERE
Coordinate System
CARTESIAN
Granule Spatial Representation
GEODETIC
Temporal Extent
2015-03-31 to Present
Concept ID
C2938663676-NSIDC_CPRD
Data State
ACTIVE
Number of Files/Granules
111190
Processing Level
2
Published
Science Keywords
Brightness Temperature ,
Surface Soil Moisture

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.

Copy Citation

ONeill, P., Chan, S., Njoku, E., Jackson, T., Bindlish, R., Chaubell, J., & Colliander, A. (2023). SMAP Enhanced L2 Radiometer Half-Orbit 9 km EASE-Grid Soil Moisture, Version 6 [Data set]. NASA National Snow and Ice Data Center Distributed Active Archive Center. https://doi.org/10.5067/BN36FXOMMC4C Date Accessed: 2026-01-29

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