MEaSUREs Global Record of Daily Landscape Freeze/Thaw Status, Version 5
Data set id:
NSIDC-0477
DOI: 10.5067/LJ6SLXNJB2CQ
This is the most recent version of these data.
Version Summary
Version Summary
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.
• 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.
Overview
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).
Parameter(s):
FREEZE/THAW
Platform(s):
DMSP 5D-2/F11, DMSP 5D-2/F13, DMSP 5D-2/F8, DMSP 5D-3/F17, GCOM-W1, Nimbus-7
Sensor(s):
AMSR2, SMMR, SSM/I, SSMIS
Data Format(s):
HDF, GIF, GeoTIFF
Temporal Coverage:
1 January 1979 to 31 December 2021
Temporal Resolution:
- 1 day
Spatial Resolution:
- 25 km
- 25 km
Spatial Reference System(s):
NSIDC EASE-Grid Global
EPSG:3410
Spatial Coverage:
N:
86.7167
S:
-86.7167
E:
179.9999
W:
-179.9999
Blue outlined yellow areas on the map below indicate the spatial coverage for this data set.
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