Hydrogeomorphic processes of thermokarst lakes with grounded-ice and floating-ice regimes on the Arctic coastal plain, Alaska

摘要: Thermokarst lakes cover > 20% of the landscape throughout much Alaskan Arctic Coastal Plain (ACP) with shallow freezing solid (grounded ice) and deeper maintaining perennial liquid water (floating ice). Thus, lake depth relative to maximum ice thickness (1·5–2·0 m) represents an important threshold that impacts permafrost, aquatic habitat, potentially geomorphic hydrologic behaviour. We studied coupled hydrogeomorphic processes 13 representing a gradient across this by analysing remotely sensed, quality, climatic data over 35-year period. Shoreline erosion rates due permafrost degradation ranged from < 0·2 m/year in very (0·4 up 1·8 deepest (2·6 m). This pattern thermokarst expansion masked detection change using sensed imagery except for shallowest stable shorelines. Changes surface area these tracked interannual variation precipitation minus evaporation (P − EL) periods full nearly dry basins. Shorter-term (2004–2008) specific conductance indicated drying all depths consistent long-term record only lakes. Our analysis suggests grounded-ice are ice-free on average 37 days longer than floating-ice resulting period evaporative loss more frequent negative P EL. These results suggest divergent responses changing climate depending created ACP Copyright © 2011 John Wiley & Sons, Ltd.