Abstract Debris-covered glaciers in the central Himalaya have now experienced several decades of sustained ice loss, manifested predominantly in glacier surface lowering. In particular, glacier surfaces of low longitudinal gradient and low ice surface velocity have developed locally complex surface topographies and undergone profound changes in supraglacial hydrology. In this study we examine the development of complex ice surface topography across six debris-covered glaciers in the Everest region over the last four decades via a new metric of glacier surface relief applied to Digital Elevation Models (DEMs). We focus in on Khumbu Glacier, and use fine spatial and temporal resolution DEMs covering a period of 28 months to quantify the contemporary contribution of ice cliff and supraglacial pond expansion to overall mass loss from stagnant areas of ice. On the broader scale, we find three common long-term changes in glacier surface topography, (1) glacier-wide expansion of high relief topography in response to ice cliff and supraglacial pond network evolution, (2) up-glacier expansion of high local relief zones that may be caused by differential sub-debris melt beneath thin debris, and (3) increase in glacier surface relief proximal to glacier termini caused by supraglacial stream incision where linked proglacial-supraglacial hydrological networks exist. Overall, we contend that these topographic measurements will be important for understanding glacier surface water storage and also the energy balance of a debris-covered glacier surface, both of which could exacerbate future ice loss and downstream meltwater supply.

中文翻译：

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珠穆朗玛峰地区碎片覆盖冰川的形态演化

摘要 喜马拉雅中部被碎屑覆盖的冰川现在已经经历了几十年的持续冰损失，主要表现为冰川表面降低。特别是低纵向梯度和低冰面速度的冰川面，局部形成了复杂的地表地形，冰上水文发生了深刻的变化。在这项研究中，我们通过应用于数字高程模型 (DEM) 的冰川表面起伏的新指标，研究了过去 40 年珠穆朗玛峰地区六个被碎片覆盖的冰川的复杂冰面地形的发展。我们专注于昆布冰川，并使用覆盖 28 个月的精细空间和时间分辨率 DEM 来量化冰崖和冰上池塘扩张对冰停滞区域整体质量损失的当代贡献。在更广泛的范围内，我们发现冰川表面地形有三种常见的长期变化，(1) 响应冰崖和冰上池塘网络演化的高地貌地形在冰川范围内的扩展，(2) 高地局部的冰川向上扩展。可能由不同次碎片融化在薄碎屑之下引起的浮雕带，以及 (3) 由冰上溪流切口引起的靠近冰川终点的冰川表面起伏增加，其中存在链接的前冰河-上冰河水文网络。全面的，