科研之友
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摘要
The sudden drainage of supraglacial lakes has been previously observed to initiate surface-to-bed hydrologic connections, which are capable of enhancing basal sliding, in regions of the Greenland Ice Sheet where ice thickness approaches 1 km. In this study, we develop a robust algorithm, which automatically detects and tracks individual supraglacial lakes using visible satellite imagery, to document the evolution of a population of West Greenland supraglacial lakes over ten consecutive melt seasons. Validation tests indicate that the algorithm is highly accurate: 99.0% of supraglacial lakes can be detected and tracked and 96.3% of reported lakes are true supraglacial lakes with accurate lake properties, such as lake area, and timing of formation and drainage. Investigation of the interannual evolution of supraglacial lakes in the context of annual melt intensity reveals that during more intense melt years, supraglacial lakes drain more frequently and earlier in the melt season. Additionally, the lake population extends to higher elevations during more intense melt years, exposing an increased inland area of the ice sheet to sudden lake drainage events. These observations suggest that increased surface meltwater production due to climate change will enhance the spatial extent and temporal frequency of lake drainage events. It is unclear whether this will ultimately increase or decrease the basal sliding sensitivity of interior regions of the Greenland Ice Sheet.
- 出版日期2012-8
