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Description

This document describes the SMAP Level-4 Surface and Root Zone Soil Moisture (SPL4SM) data product, which consists of: (1) SMAP L4 9 km EASE-Grid Surface and Root Zone Soil Moisture Geophysical Data (SPL4SMGP). (2) SMAP L4 9 km EASE-Grid Surface and Root Zone Soil Moisture Analysis Update (SPL4SMAU). (3) SMAP L4 9 km EASE-Grid Surface and Root Zone Soil Moisture Land Model Constants (SPL4SMLM).

For each product, input SMAP L-band brightness temperatures from descending and ascending half-orbit satellite passes (approximately 6:00 a.m. and 6:00 p.m. local solar time, respectively) are assimilated into a land surface model that is gridded using an Earth-fixed, global, cylindrical 9 km Equal-Area Scalable Earth Grid, Version 2.0 (EASE-Grid 2.0) projection.
Note: These data are Beta-release quality, meaning that they have not undergone full validation and may still contain significant errors.

Version Description

First public data release

Product Summary

Platforms
SMAP
Instruments
SMAP L-BAND RADAR
Spatial Extent

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

Spatial Resolution
9 Kilometers x 9 Kilometers
Location
GLOBAL LAND
Coordinate System
CARTESIAN
Granule Spatial Representation
CARTESIAN
Temporal Extent
2015-03-31 to 2016-04-22
Temporal Resolution
3 Hour
Concept ID
C4114261060-NSIDC_CPRD
Data State
DEPRECATED
Number of Files/Granules
0
Processing Level
4
Published
Updated
Science Keywords
Soil Moisture/Water Content

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

Reichle, R., De Lannoy, G., Koster, R., Crow, W., & Kimball, J. (2015). SMAP L4 9 km EASE-Grid Surface and Root Zone Soil Moisture Analysis Update, Version 1 [Data set]. NASA National Snow and Ice Data Center Distributed Active Archive Center. https://doi.org/10.5067/SHSINYSFEV8L Date Accessed: 2026-06-16

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