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Description

This Level-3 (L3) product provides a daily composite of landscape freeze/thaw conditions retrieved by the Soil Moisture Active Passive (SMAP) radiometer from 6:00 a.m. descending and 6:00 p.m. ascending half-orbit passes. SMAP L-band brightness temperatures are used to derive freeze/thaw state and transition data, which are then resampled to both an Earth-fixed, Northern Hemisphere azimuthal 36 km Equal-Area Scalable Earth Grid (EASE-Grid 2.0), and to an Earth-fixed global 36 km EASE-Grid 2.0.

Version Description

Changes to this version include: • Minor bug fix to correct the indexing of bits in the AMSER-E never-frozen never-thawed maps • An improved processing methodology was applied to the input 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: 85.044 S: 45 E: 180 W: -180

,

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

Spatial Resolution
36 Kilometers x 36 Kilometers
Spatial Reference System(s)
Multiple EPSG codes (see User Guide)
Location
GLOBAL ,
NORTHERN HEMISPHERE
Coordinate System
CARTESIAN
Granule Spatial Representation
CARTESIAN
Temporal Extent
2015-03-31 to Present
Temporal Resolution
1 Day
Concept ID
C2938664170-NSIDC_CPRD
Data State
ACTIVE
Number of Files/Granules
3986
Processing Level
3
Published
Science Keywords
Transition Direction

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

Xu, X., Dunbar, R., Derksen, C., Colliander, A., Kim, Y., & Kimball, J. (2023). SMAP L3 Radiometer Global and Northern Hemisphere Daily 36 km EASE-Grid Freeze/Thaw State, Version 4 [Data set]. NASA National Snow and Ice Data Center Distributed Active Archive Center. https://doi.org/10.5067/LQQ5I3QVGFTU Date Accessed: 2026-04-30

Documents

Publications Citing This Dataset

Filters
Title Year Author Topic
Predicting Freeze-Thaw States in Alaska Permafrost Landscapes using Ahajjam, A., Soaper, M., Chance, R., Chandler, J., Pasch, T. Heat Flux, Air Temperature, Skin Temperature, Specific Humidity, Water Vapor, Precipitation Rate, Snow/Ice, Evaporation, Latent Heat Flux, Latent Heat Flux, Sensible Heat Flux, Diffusion, Surface Winds, Wind Speed, U/V Wind Components, Wind Stress, Wind Stress, Surface Roughness, Planetary Boundary Layer Height, Ice Fraction, Atmospheric Radiation, Longwave Radiation, Shortwave Radiation, Radiative Flux, Radiative Forcing, Surface Radiative Properties, Albedo, Emissivity, Cloud Properties, Cloud Fraction, Cloud Optical Depth/Thickness, Skin Temperature, Sea Surface Skin Temperature, Geopotential Height, Altitude, Surface Temperature, Upper Air Temperature, Dew Point Temperature, Cloud Top Temperature, Atmospheric Winds, Surface Winds, Upper Level Winds, U/V Wind Components, Vertical Wind Velocity/Speed, Atmospheric Pressure, Sea Level Pressure, Cloud Top Pressure, Sea Level Pressure, Surface Pressure, Total Precipitable Water, Cloud Liquid Water/Ice, Atmospheric Water Vapor, Atmospheric Ozone, Oxygen Compounds, Boundary Layer Winds, Total Ozone, Soil Heat Budget, Soil Heat Budget, Soil Temperature, Soil Temperature, Soil Infiltration, Soil Infiltration, Soil Moisture/Water Content, Surface Soil Moisture, Root Zone Soil Moisture, Soil Moisture/Water Content, Surface Water, Runoff Rate, Average Flow, Average Flow, Precipitation, Snow Depth, Snow Melt, Snow/Ice Temperature, Leaf Area Index (LAI), Leaf Area Index (LAI), Brightness Temperature, Transition Direction
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