Temporal and spatial pattern of thermokarst lake area changes at Yukon Flats,Alaska |
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| Authors: | Min Chen Joel C Rowland Cathy J Wilson Garrett L Altmann Steven P Brumby |
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| Institution: | 1. Division of Earth and Environmental Sciences, Los Alamos National Laboratory, Los Alamos, NM, USA;2. Department of Forest Sciences, University of Alaska, Fairbanks, AK, USA;3. Division of Intelligence and Space Research, Los Alamos National Laboratory, Los Alamos, NM, USA |
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| Abstract: | To better understand the linkage between lake area change, permafrost conditions and intra‐annual and inter‐annual variability in climate, we explored the temporal and spatial patterns of lake area changes for a 422 382‐ha study area within Yukon Flats, Alaska using Landsat images of 17 dates between 1984 and 2009. Only closed basin lakes were used in this study. Among the 3529 lakes greater than 1 ha, closed basin lakes accounted for 65% by number and 50% by area. A multiple linear regression model was built to quantify the temporal change in total lake area with consideration of its intra‐annual and inter‐annual variability. The results showed that 80.7% of lake area variability was attributed to intra‐annual and inter‐annual variability in local water balance and mean temperature since snowmelt (interpreted as a proxy for seasonal thaw depth). Another 14.3% was associated with long‐term change. Among 2280 lakes, 350 lakes shrank, and 103 lakes expanded. The lakes with similar change trends formed distinct clusters, so did the lakes with similar short term intra‐annual and inter‐annual variability. By analysing potential factors driving lake area changes including evaporation, precipitation, indicators for regional permafrost change, and flooding, we found that ice‐jam flooding events were the most likely explanation for the observed temporal pattern. In addition to changes in the frequency of ice jam flooding events, the observed changes of individual lakes may be influenced by local variability in permafrost distributions and/or degradation. Copyright © 2012 John Wiley & Sons, Ltd. |
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| Keywords: | thermokarst lakes temporal and spatial analysis climatic change ice‐jam flooding permafrost Yukon Flats in Alaska |
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