Ground Reference and Ancillary Data Validation of Freeze-Thaw State Products of Alaska

The freeze-thaw state of the landscape is a good indicator of growing season length, metabolic activity, root and soil respiration, and biogeochemical cycling in high latitude regions like Alaska. The increase in biological productivity and hydrological activity that comes with the arrival of the summer snow- and ice-free period can be estimated by microwave remote sensing systems because of the rise in the dielectric constant during the thawed period, which registers as marked shifts in the time series progression acquired by these data. Our study involves the comparison of high-frequency microwave remote sensing data, such as NASA's QuickSCAT sensor, with daily records of meteorological variables from the National Climatic Data Center's Global Historical Climatology Network (NCDC GHCN-Daily) and Natural Resources Conservation Service's Snowpack Telemetry (SNOTEL) network. These variables include soil temperature profiles, snowfall, and snow depth. A change detection algorithm was used to classify the microwave time series data as frozen or thawed. The station data were then utilized to validate the accuracy of the algorithm's product.