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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: - Dual Channel Algorithm (DCA) replaces Single Channel Algorithm – Vertical (SCA-V) as baseline algorithm. - Addition of north-polar grid soil moisture retrievals which are intended to mitigate the distortion of global-grid cells at high northern latitudes (> 50N). These are presented in the products in the new Soil_Moisture_Retrieval_Data_Polar data group. - Addition of the soil texture elements organic_content and sand_fraction in both global and polar grid groups. - Bulk_density maximum value changed from 1 to 2.65.

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
Spatial Reference System(s)
Multiple EPSG codes (see User Guide)
Location
GLOBAL LAND ,
NORTHERN HEMISPHERE
Coordinate System
CARTESIAN
Granule Spatial Representation
GEODETIC
Temporal Extent
2015-03-31 to 2023-12-04
Temporal Resolution
49 Minute
Concept ID
C2830470122-NSIDC_CPRD
Data State
DEPRECATED
Number of Files/Granules
0
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. (2021). SMAP Enhanced L2 Radiometer Half-Orbit 9 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/LOT311EZHH8S Date Accessed: 2026-06-09

Documents

Publications Citing This Dataset

Filters
Title Year Author Topic
Low-Rank Gap Filling and Downscaling for SMAP Soil Moisture Datasets Beale, Kevin, Bras, Rafael L., Romberg, Justin Brightness Temperature, Surface Soil Moisture, Land Use/Land Cover Classification, Soil Classification, Soil Moisture/Water Content, Soil Temperature, Vegetation Water Content, SIGMA NAUGHT, Soil Bulk Density, Soil Moisture/Water Content, Soil Temperature, Soil Texture, Soil Texture, Land Surface Temperature, Precipitation Indices, Soil Moisture, Soil Temperature, Precipitation Amount
Divergent response of crops and natural vegetation to the record-breaking extreme precipitation event in 2020 modulated by topography Chen, Jiuyi, Qiu, Bo, Guo, Weidong, Li, Lingfeng, Miao, Xin Land Use/Land Cover Classification, Brightness Temperature, Surface Soil Moisture
Performance of SMOS Soil Moisture Products over Core Validation Sites Colliander, A., Kerr, Y., Wigneron, J.-P., Al-Yaari, A., Rodriguez-Fernandez, N., Li, X., Chaubell, J., Richaume, P., Mialon, A., Asanuma, J., Berg, A., Bosch, D. D., Caldwell, T., Cosh, M. H., Collins, C. Holifield, Martinez-Fernandez, J., McNairn, H., Seyfried, M. S., Starks, P. J., Su, Z., Thibeault, M., Walker, J. P. Brightness Temperature, Surface Soil Moisture
Systematic daytime increases in atmospheric biases linked to dry soils in irrigated areas in Indian operational forecasts Barton, Emma J., Taylor, C. M., Mitra, A. K., Jayakumar, A. Vegetation Water Content, Soil Moisture/Water Content, Skin Temperature, Emissivity, Land Surface Temperature, Precipitation, Precipitation Amount, Precipitation Rate, Snow, Rain, Brightness Temperature, Surface Soil Moisture
Robustness of Vegetation Optical Depth Retrievals Based on L-Band Global Radiometry Chaparro, David, Feldman, Andrew F., Chaubell, Mario Julian, Yueh, Simon H., Entekhabi, Dara Vegetation Index, Normalized Difference Vegetation Index (NDVI), Enhanced Vegetation Index (EVI), Precipitation, Precipitation Amount, Precipitation Rate, Snow, Rain, Surface Soil Moisture, Brightness Temperature
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