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Description

This data set, part of the NASA Making Earth System Data Records for Use in Research Environments (MEaSUREs) program, contains a global record of the daily freeze/thaw status of the landscape. The record is derived from radiometric brightness temperatures acquired between 1979 and 2021 by four satellite-based, passive microwave sensors: the Scanning Multichannel Microwave Radiometer (SMMR), the Special Sensor Microwave/Imager (SSM/I), the Special Sensor Microwave Imager/Sounder (SSMIS), and the Advanced Microwave Scanning Radiometer 2 (AMSR2).

Version Description

This version update includes:
• Extended F/T record to 2021;
• Applied modified seasonal threshold algorithm (MSTA) for the F/T classification where MSTA Tb reference F/T conditions are calibrated annually for each pixel using ERA5 (Hersbach et al., 2018) daily surface air temperature (SAT) records;
• Constant threshold applied over global permanent snow/ice regions to determine the F/T state when the correlation (r-value) between ERA5 SAT and brightness temperature (Tb) is low (absolute value of r less than 0.5). The constant Tb threshold used to distinguish F/T events was determined annually using mean Tb threshold values derived from pixels with higher correlation (absolute value of r greater than 0.5) between SSM/I Tb and ERA5 SAT;
• Applied diurnal amplitude variation (DAV) of Tb from ascending and descending orbital overpass retrievals as an additional step to confirm thaw condition for the PM overpass only;
• Updated quality control (QC) flags included in the product granules identifying grid cells and days with missing and interpolated Tb observations, and characterizing extensive open water bodies, complex terrain, and precipitation events;
• Updated annual data quality assurance (QA) maps included to indicate product performance and reliability.

Product Summary

Platforms
DMSP 5D-2/F11 ,
DMSP 5D-2/F13 ,
DMSP 5D-2/F8 ,
DMSP 5D-3/F17 ,
FY-3B ,
GCOM-W1 ,
Nimbus-7
Instruments
SSM/I ,
SSMIS ,
MWRI ,
AMSR2 ,
SMMR
Spatial Extent

N: 86.7167 S: -86.7167 E: 179.9999 W: -179.9999

Spatial Resolution
25 Kilometers x 25 Kilometers
Geographic Region
GLOBAL
Coordinate System
CARTESIAN
Granule Spatial Representation
CARTESIAN
Temporal Extent
1979-01-01 to 2023-12-31
Concept ID
C3287097610-NSIDC_CPRD
Data State
COMPLETE
Number of Files/Granules
49401
Processing Level
3
Published
Science Keywords
Freeze/Thaw

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

Kim, Y., Kimball, J., Du, J., & Glassy, J. (2021). MEaSUREs Global Record of Daily Landscape Freeze/Thaw Status, Version 5 [Data set]. NASA National Snow and Ice Data Center Distributed Active Archive Center. https://doi.org/10.5067/LJ6SLXNJB2CQ Date Accessed: 2025-12-24

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