Long‐term shifts in feedbacks among glacier surface change, melt generation and runoff, McMurdo Dry Valleys, Antarctica
Long‐term shifts in feedbacks among glacier surface change, melt generation and runoff, McMurdo Dry Valleys, Antarctica
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DOI：
10.1002/hyp.14292
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发表时间：
2021-06
影响因子：
3.2
通讯作者：
A. Bergstrom;M. Gooseff;A. Fountain;M. Hoffman
中科院分区：
文献类型：
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作者：
A. Bergstrom;M. Gooseff;A. Fountain;M. Hoffman
南极洲麦克默多干谷（MDV）的冰川是这一极地沙漠的主要径流来源。由于夏季气温徘徊在0°C附近，能量平衡的微小变化会强烈影响融水的生成。在这里，我们表明，增加表面粗糙度，这改变了湍流之间的能量转移的冰表面和大气，产生一个可检测的增加融水径流。在冰川的低海拔地区，在重复激光雷达调查之间的13年里，盆地状地形变得明显粗糙，产生了更大的融化。相比之下，在较高海拔较光滑的冰没有表现出可检测到的粗糙度变化。我们提出了一个冰川表面变化周期的概念模型，作为气候强迫的结果，冰川表面从以升华为主转变为越来越以融化为主，这在长时间的冷却期下是可逆的。这项研究推进了我们对温暖季节对极地冰川影响的理解。
Glaciers of the McMurdo dry valleys (MDVs) Antarctica are the main source of streamflow in this polar desert. Because summer air temperatures hover near 0°C small changes in the energy balance strongly affect meltwater generation. Here we demonstrate that increased surface roughness, which alters the turbulent transfer of energy between the ice surface and atmosphere, yields a detectable increase in meltwater runoff. At low elevations on the glaciers, basin‐like topography became significantly rougher over 13 years between repeat lidar surveys, yielding greater melt. In contrast, the smoother ice at higher elevation exhibited no detectable change in roughness. We pose a conceptual model of the cycle of glacier surface change as a result of climate forcing whereby glacier surfaces transition from being dominated by sublimation to becoming increasingly melt‐dominated, which is reversible under prolonged cool periods. This research advances our understanding of warm season effects on polar glaciers.