Rapid submarine melting driven by subglacial discharge, LeConte Glacier, Alaska
Rapid submarine melting driven by subglacial discharge, LeConte Glacier, Alaska
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阿拉斯加勒孔特冰川冰下放电驱动的海底快速融化
DOI：
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
M. Fahnestock
中科院分区：
文献类型：
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作者：
R. Motyka;W. P. Dryer;J. Amundson;M. Truffer;M. Fahnestock
我们表明，冰下淡水排放是导致潮水冰川海底融化速率较高的主要过程。这种浮力排放会吸入温暖的海水，使其在沿海底冰川面的湍流上升流中被夹带，从而融化冰川冰。为了捕捉冰下排放对海底融化的影响，我们于2012年夏末在阿拉斯加的勒孔特冰川进行了为期4天的水文断面测量。一场大暴雨使我们能够记录冰下排放大幅变化的影响。我们发现，由于暴雨的影响，强烈的海底融化通量从9.1±1.0米/天增加到16.8±1.3米/天（冰面等效前沿消融量）。随着全球持续变暖以及冰川径流预计会增加，我们的研究结果凸显了冰下排放增加将对潮水出口系统产生的直接影响。在对冰川对未来变暖及径流增加的响应进行建模时，必须考虑这些影响。
We show that subglacial freshwater discharge is the principal process driving high rates of submarine melting at tidewater glaciers. This buoyant discharge draws in warm seawater, entraining it in a turbulent upwelling flow along the submarine face that melts glacier ice. To capture the effects of subglacial discharge on submarine melting, we conducted 4 days of hydrographic transects during late summer 2012 at LeConte Glacier, Alaska. A major rainstorm allowed us to document the influence of large changes in subglacial discharge. We found strong submarine melt fluxes that increased from 9.1 ± 1.0 to 16.8 ± 1.3 m d−1 (ice face equivalent frontal ablation) as a result of the rainstorm. With projected continued global warming and increased glacial runoff, our results highlight the direct impact that increases in subglacial discharge will have on tidewater outlet systems. These effects must be considered when modeling glacier response to future warming and increased runoff.