Temporal Behavior of Lake Size-Distribution in a Thawing Permafrost Landscape in Northwestern Siberia
Temporal Behavior of Lake Size-Distribution in a Thawing Permafrost Landscape in Northwestern Siberia
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DOI：
10.3390/rs6010621
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发表时间：
2014-01
期刊：
影响因子：
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通讯作者：
J. Karlsson;S. Lyon;G. Destouni
中科院分区：
文献类型：
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作者：
J. Karlsson;S. Lyon;G. Destouni
北极变暖改变了区域水文系统，因为永久冻土融化增加了活动层厚度，从而改变了水流通过景观的路径。此外，冻土融化可能会改变深层和浅层地下水与地表水之间的连通性，从而改变陆地水的平衡和分布。北极的热岩溶湖泊和湿地为了解这种变化提供了一个窗口，因为这些景观要素依赖于永久冻土，是北极低地地区最具活力和最广泛的特征。在这项研究中，我们使用Landsat遥感图像调查潜在的变化，在热岩溶湖泊的大小分布，这可能会带来永久冻土融化，在三个不同的时间段（1973年，1987年至1988年，2007年至2009年）在西伯利亚西北部的三个水文流域。结果显示，随着时间的推移，总面积和湖泊数量的波动，与稳定的湖泊出现和消失的湖泊。在整个流域尺度上，没有任何迹象表明热岩溶湖泊面积或湖泊规模丰度随时间的持续长期变化。这种统计时间的一致性表明，空间可变的变化对当地永久冻土条件的影响，推动了个别湖泊的变化，确实发生了随着时间的推移。这些结果突出了使用多时相遥感数据的重要性，这些数据可以揭示复杂的时空变化，将波动与持续变化趋势区分开来，以便准确解释热岩溶湖泊变化及其在气候和永久冻土变化期间的可能驱动因素。
Arctic warming alters regional hydrological systems, as permafrost thaw increases active layer thickness and in turn alters the pathways of water flow through the landscape. Further, permafrost thaw may change the connectivity between deeper and shallower groundwater and surface water altering the terrestrial water balance and distribution. Thermokarst lakes and wetlands in the Arctic offer a window into such changes as these landscape elements depend on permafrost and are some of the most dynamic and widespread features in Arctic lowland regions. In this study we used Landsat remotely sensed imagery to investigate potential shifts in thermokarst lake size-distributions, which may be brought about by permafrost thaw, over three distinct time periods (1973, 1987–1988, and 2007–2009) in three hydrological basins in northwestern Siberia. Results revealed fluctuations in total area and number of lakes over time, with both appearing and disappearing lakes alongside stable lakes. On the whole basin scales, there is no indication of any sustained long-term change in thermokarst lake area or lake size abundance over time. This statistical temporal consistency indicates that spatially variable change effects on local permafrost conditions have driven the individual lake changes that have indeed occurred over time. The results highlight the importance of using multi-temporal remote sensing data that can reveal complex spatiotemporal variations distinguishing fluctuations from sustained change trends, for accurate interpretation of thermokarst lake changes and their possible drivers in periods of climate and permafrost change.