Regional lake ice meltout patterns near Barrow, Alaska

Abstract The coastal plain of Arctic Alaska contains many thousands of lakes developed in continuous permafrost, which are ice-free for only 3–4 months each year. The spatial pattern of lake ice meltout for 1870 lakes (>10 ha) in a ~9200 km2 study area near Barrow, Alaska, is analyzed using five Landsat scenes spanning a 35-year record. For each available year, a spectra-based clustering algorithm is used to differentiate water from ice during springtime meltout and is overlain on a common lake shoreline template to determine the percentage of ice covering each lake. Analysis of these ‘ice-cover ratios’ for each scene reveals that there is pronounced interannual variation in the timing of lake ice meltout. The spatial pattern consistently demonstrates an increase in the percentage of ice coverage on lakes further north, reflecting the regional climatic gradient. However, the ice cover on many lakes near the northeastern coast persists for a substantially longer period into summer due to cooler temperature...