Synthetic aperture radar (SAR) satellite data were used to map late winter liquid water presence below ice for lakes within a 168,000 km2 study area on the North Slope coastal plain of Alaska. Automated digital processing techniques were used to preprocess and classify 36 ERS-2 images acquired during April 2009. Lakes within the study area were extracted from the imagery and classified to produce frozen (no liquid water present) and unfrozen (liquid water present under ice) classes. Bathymetric data from 105 lakes were compiled from existing sources and were used as validation for the classification results based on an expected maximum ice depth of 1.6 m. Lake locations with a depth of less than 1.6 m were considered to be frozen while [...]
