Temporal coverage: 1 January 1979 - 31 December 2010
The Daily Landscape Freeze/Thaw layer shows the predominant frozen or non-frozen (thawed) status of the landscape in vegetated regions where seasonal frozen temperatures are a major constraint to ecosystem processes. It is derived using a temporal change classification of calibrated radiometric brightness temperatures at 37 GHz frequency from Scanning Multichannel Microwave Radiometer (SMMR) and Special Sensor Microwave Imager (SSM/I, SSMIS) sensor records available from Nimbus-7 and Defense Meteorological Satellite Program (DMSP) satellites.
The freeze/thaw layer is useful for assessing the impact of freeze/thaw variations on vegetation growing seasons and land-atmosphere carbon exchange; snow cover, permafrost and active layer properties; surface energy and water budgets; distinguishing freeze/thaw dynamics in accordance with regional terrain features, weather events, seasonal and annual climate anomalies, and long-term climate changes. The layer distinguishes 4 states: frozen, non-frozen (thawed), transitional (AM frozen, PM thawed) and inverse transitional (AM thawed, PM frozen).
The MEaSUREs record of daily landscape freeze/thaw status is produced in a global equal area projection gridded to a 25 km spatial resolution; temporal resolution is daily, as derived from morning (AM) and afternoon (PM) sensor brightness temperature retrievals.
References: NSIDC - MEaSUREs Global Record of Daily Landscape Freeze/Thaw Status, Version 3; Freeze/Thaw Earth System Data Record