Shifting balance of thermokarst lake ice regimes across the Arctic Coastal Plain of northern Alaska

[1] The balance of thermokarst lakes with bedfastand floating-ice regimes across Arctic lowlands regulates heat storage, permafrost thaw, winter-water supply, and overwintering aquatic habitat. Using a time-series of late-winter synthetic aperture radar (SAR) imagery to distinguish lake ice regimes in two regions of the Arctic Coastal Plain of northern Alaska from 2003–2011, we found that 18% of the lakes had intermittent ice regimes, varying between bedfastice and floating-ice conditions. Comparing this dataset with a radar-based lake classification from 1980 showed that 16% of the bedfast-ice lakes had shifted to floating-ice regimes. A simulated lake ice thinning trend of 1.5 cm/yr since 1978 is believed to be the primary factor driving this form of lake change. The most profound impacts of this regime shift in Arctic lakes may be an increase in the landscape-scale thermal offset created by additional lake heat storage and its role in talik development in otherwise continuous permafrost as well as increases in over-winter aquatic habitat and winterwater supply. Citation: Arp, C. D., B. M. Jones, Z. Lu, andM. S. Whitman (2012), Shifting balance of thermokarst lake ice regimes across the Arctic Coastal Plain of northern Alaska, Geophys. Res. Lett., 39, L16503, doi:10.1029/2012GL052518.