Skip to main content

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
4103
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 [Dataset]. NASA National Snow and Ice Data Center Distributed Active Archive Center. https://doi.org/10.5067/LQQ5I3QVGFTU Date Accessed: 2026-09-15

Documents

No Results

QUESTIONS & SUPPORT

Have a question?

Get help with NASA Earth science data, datasets, tools, services, and metadata on the Earthdata Forum. Experienced staff in the data user community review and answer questions.

Get help on Earthdata Forum
Earthdata
Forum

Publications Citing This Dataset

Filters
Title Year Author Topic
A Hybrid Compact Polarimetry GNSS-R Analysis of the Earth's Cryosphere Rodriguez-Alvarez, Nereida, Munoz-Martin, Joan Francesc, Bosch-Lluis, Xavier, Oudrhiri, Kamal Sea Ice Concentration, Bathymetry, Bed Elevation, Glacier/Ice Sheet Thickness, Terrain Elevation, Transition Direction
Simultaneous retrieval of surface roughness parameters for bare soils from combined activepassive microwave SMAP observations Fluhrer, Anke, Jagdhuber, Thomas, Akbar, Ruzbeh, O'Neill, Peggy E., Entekhabi, Dara Carbon, Cation Exchange Capacity, Organic Matter, ORBITAL CHARACTERISTICS, RADAR IMAGERY, SIGMA NAUGHT, Brightness Temperature, Soil Moisture/Water Content, Transition Direction
Potential Use of NASA's Soil Moisture Active Passive FreezeThaw Tool to Assist in Minnesota Seasonal Load Restriction Timing Kraatz, Simon, Miller, Heather J., Poirier, Benjamin J, Moradi, Mahsa, Jacobs, Jennifer M. Transition Direction
Simultaneous retrieval of surface roughness parameters from combined active-passive SMAP observations Fluhrer, Anke, Jagdhuber, Thomas, Akbar, Ruzbeh, O'Neill, Peggy, Entekhabi, Dara ORBITAL CHARACTERISTICS, RADAR IMAGERY, SIGMA NAUGHT, Brightness Temperature, Soil Moisture/Water Content, Transition Direction
Parameterization of the freeze/thaw discriminant function algorithm using dense in-situ observation network data Wang, Pingkai, Zhao, Tianjie, Shi, Jiancheng, Hu, Tongxi, Roy, Alexandre, Qiu, Yubao, Lu, Hui Transition Direction
Advantages and limitations of L-band bistatic radar remote sensing of landscape freeze/thaw state Chew, C., Podest, E., McDonald, K. C., Steiner, N. Transition Direction
You're viewing 6 of 6