Gulf of Alaska ice-marginal lake area change over the Landsat record and potential physical controls
Gulf of Alaska ice-marginal lake area change over the Landsat record and potential physical controls
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DOI：
10.5194/tc-15-3255-2021
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发表时间：
2021-07-15
期刊：
影响因子：
5.2
通讯作者：
Huss, Matthias
中科院分区：
文献类型：
--
作者：
Field, Hannah R.;Armstrong, William H.;Huss, Matthias
与冰川边缘接触的湖泊会影响冰川演变以及下游的生物物理系统、洪水灾害和水资源。最近的工作表明，冰川损耗和冰缘湖演变之间的正反馈，虽然精确的物理控制没有得到很好的理解。在这里，我们量化了1984-2018年北美西北部未充分研究的冰缘湖面积变化，并调查了气候，地形和冰川对湖泊面积变化的影响。我们描绘了采样湖泊周长的时间序列（n = 107个湖泊），发现区域湖泊面积总体增加了58%，单个冰前湖泊平均增加了1.28 km（2）（125%），冰坝湖泊平均减少了0.04 km（2）（15%）。气候再分析资料的统计分析表明，夏季气温和冬季降水的变化对湖泊面积变化的直接影响很小。利用现有的观测和模拟冰川特征的数据集，我们发现，大，宽的冰川与厚厚的湖泊附近的冰与湖泊面积变化的最快速度，特别是在他们已经经历了快速的质量损失在最近的时间。我们观察到一个二分法，其中大，低海拔沿海冰前湖的绝对值变化最大，而小，高海拔的内部湖泊的相对值变化最大。一般来说，变化最快的湖泊并没有经历最剧烈的温度或降水变化，也没有与最高的冰川质量损失率相关。我们的工作表明，虽然气候和冰川因素必须发挥一定的作用，在确定湖泊面积的变化，湖泊的具体几何形状和地形环境的影响，这些外部控制。
Lakes in contact with glacier margins can impact glacier evolution as well as the downstream biophysical systems, flood hazard, and water resources. Recent work suggests positive feedbacks between glacier wastage and ice-marginal lake evolution, although precise physical controls are not well understood. Here, we quantify ice-marginal lake area change in understudied northwestern North America from 1984-2018 and investigate climatic, topographic, and glaciological influences on lake area change. We delineate time series of sampled lake perimeters (n = 107 lakes) and find that regional lake area has increased 58% in aggregate, with individual proglacial lakes growing by 1.28 km(2) (125 %) and ice-dammed lakes shrinking by 0.04 km(2) (15 %) on average. A statistical investigation of climate reanalysis data suggests that changes in summer temperature and winter precipitation exert minimal direct influence on lake area change. Utilizing existing datasets of observed and modeled glacial characteristics, we find that large, wide glaciers with thick lake-adjacent ice are associated with the fastest rate of lake area change, particularly where they have been undergoing rapid mass loss in recent times. We observe a dichotomy in which large, low-elevation coastal proglacial lakes have changed most in absolute terms, while small, interior lakes at high elevation have changed most in relative terms. Generally, the fastest-changing lakes have not experienced the most dramatic temperature or precipitation change, nor are they associated with the highest rates of glacier mass loss. Our work suggests that, while climatic and glaciological factors must play some role in determining lake area change, the influence of a lake's specific geometry and topographic setting overrides these external controls.