A lake’s ice regime (freezing solid to the bed or if liquid water remaining beneath the ice all winter) strongly affects over-wintering fish habitat, energy and water balance, permafrost stability, and is important for determining winter water sources. Trends toward thinner ice are causing a regime shift in shallow Arctic lakes in some areas.
We compare lake ice regimes from 1992-2010 using synthetic aperture radar (SAR) data in four geographic regions of the Alaska Arctic Coastal plain, to determine trends in the area of lake ice that remains bedfast (BF) and the area of floating lake ice that retains liquid water beneath the surface (FI) even at maximum ice thickness. We use a no-bias equal-error threshold approach that accounts for changes in backscatter intensity from lake ice due to aging instruments, different platforms, and ice conditions. I will present preliminary results and compare trends in percentage of bedfast ice with observed and simulated maximum ice thickness in each region.