SMAP L3 Radiometer Global and Northern Hemisphere Daily 36 km EASE-Grid Freeze/Thaw State, Version 3 (SPL3FTP)
Data set:
This is the most recent version of these data.
Version Summary
Changes to this version include:
- Adjusted the freeze/thaw reference states for the normalized polarization ratio (NPR) algorithm per the improved Level-1 brightness temperature recalibration. The freezing reference averages from 2016-2020 and the thaw reference averages from 2015-2019.
- Adjusted the reference states for the Single-Channel V (SCV) algorithm per the update of the GEOS-FP surface and soil temperature profiles.
- Improved the never frozen/never thawed masks for false-flag mitigation by:
* extending the temporal extent of the AMSR-E source data to include data through 2019
* blending in a GEOS-FP temperature climatology for 2015-2020 using a loose ±10 ºC criterion for fully-frozen or fully-thawed conditions.
- The product data structure, content, and processor code are otherwise unchanged from the previous version.

For the full major and minor version history, go to


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.
Data Format(s):
Temporal Coverage:
31 March 2015 to present
Temporal Resolution:
1 day
Spatial Resolution:
36 km
36 km
Spatial Coverage:

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