In High Mountain Asia, human-induced climate warming threatens the cryosphere. Expected long-term reductions in future runoff from glacial catchments raises concerns regarding the sustainability of these natural ‘water towers’ and the implications of reduced water availability for regional human and ecological systems. Ice-debris landforms (I-DL), containing ice whether moving or not include rock glaciers and ice-cored moraines, and are likely to be climatically more resilient than debris-covered and debris-free glaciers. Recent work has shown that rock glaciers contain globally valuable water supplies yet over High Mountain Asia information regarding their number, spatial distribution, morphometric characteristics and water content are scarce. Here, we present the first systematic estimate of the current extent and distribution of rock glaciers for a subset of High Mountain Asia (the Himalaya). A sample of 2070 intact and relict rock glaciers were digitized on Google Earth imagery from the Western, Central and Eastern Himalaya regions and then quantitative and qualitative characteristics were analysed regionally based on topographic data from the NASA Shuttle Radar Topography Mission (SRTM) Version 3.0 and then aggregated across the Himalaya using an “upscaling” method. The majority of the digitized landforms (∼65%) were categorised as intact rock glaciers (i.e., ice-debris Landforms, or I-DLs, containing ice) and the remainder as relict rock glaciers (i.e., discrete debris accumulations or DDAs, not containing ice). They range in elevation from 3225 to 5766 m a.s.l., with the lowest in the Central Himalaya. Sampled relict and intact rock glaciers are primarily situated on northern quadrants. Over the entire Himalaya, we identified ∼25,000 landforms, with a total estimated areal coverage of 3747 km. The area upscaling method was validated in the Manaslu region of Nepal using high-resolution Planet data (5 m) and freely available, fine spatial resolution optical satellite data accessed through Google Earth Pro and ESRI basemaps. In absence of complete rock glacier inventories over the Himalaya, our approach proves useful to investigate the nature, distribution and infer potential future behaviour of these landforms across the Himalaya in a changing climate.

中文翻译：

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喜马拉雅山岩石冰川分布


在亚洲高山地区，人类引起的气候变暖威胁着冰冻圈。冰川集水区未来径流预计将长期减少，这引起了人们对这些天然“水塔”的可持续性以及可用水量减少对区域人类和生态系统影响的担忧。冰残骸地貌（I-DL），无论是否移动，都含有冰，包括岩石冰川和冰芯冰碛，并且可能比残骸覆盖和无残骸冰川更具气候弹性。最近的研究表明，岩石冰川含有全球宝贵的水源，但亚洲高山地区有关其数量、空间分布、形态特征和含水量的信息却很少。在这里，我们首次对亚洲高山（喜马拉雅山）部分地区岩石冰川的当前范围和分布进行了系统估计。在来自喜马拉雅山西部、中部和东部地区的 Google 地球图像上对 2070 个完整和残存的岩石冰川样本进行了数字化，然后根据 NASA 航天飞机雷达地形任务 (SRTM) 3.0 版和然后使用“升级”方法在喜马拉雅山上进行聚合。大多数数字化地貌（~65%）被归类为完整的岩石冰川（即，冰碎片地貌，或 I-DL，含有冰），其余的被归类为残余岩石冰川（即，离散碎片堆积或 DDA，而不是含有冰）。它们的海拔范围为 3225 米至 5766 米，海拔最低的是喜马拉雅山中部。取样的遗迹和完整的岩石冰川主要位于北象限。 在整个喜马拉雅山，我们识别了约 25,000 个地貌，估计总面积覆盖范围为 3747 平方公里。使用高分辨率行星数据 (5 m) 以及通过 Google Earth Pro 和 ESRI 底图访问的免费提供的精细空间分辨率光学卫星数据，在尼泊尔马纳斯鲁地区验证了面积放大方法。由于喜马拉雅山上缺乏完整的岩石冰川清单，我们的方法被证明有助于调查喜马拉雅山上这些地貌在气候变化下的性质、分布和推断未来的潜在行为。