Abstract Glacier velocity is one of the important parameters to know about glacier dynamics, its mass and health. Understanding glacier velocity also assists in the analysis of ice thickness, ice flux and mass balance. Furthermore, basin/sub-basin wise studies are helpful to understand the climate change over that region instead of monitoring individual glaciers. In the current study, the spatial distribution of glacier velocity is generated for the entire Chandra and Bhaga sub-basins, in the Lahaul-Spiti district of Himachal Pradesh, India, using Advanced Land Observing Satellite-2/Phased Array type L-band Synthetic Aperture Radar-2 (ALOS-2/PALSAR-2) differential interferometry pair images with a 14-days temporal gap. The glaciers in Chandra sub-basin are found to have a high flow rate as compared to the glaciers in Bhaga sub-basin. Local slope and ice thickness, which decrease towards the terminus in general, control the movement of valley glaciers, and lower movement rate is observed for most of glaciers towards the terminus/frontal area. However, a few glaciers of Bhaga sub-basin demonstrate an accelerated movement in their frontal areas. This irregular behaviour is also studied in this work and it is discovered that terrain slope and influx of melting water from adjacent glaciers are the major causes for such behaviour of these glaciers. They are, therefore, prone to accelerated mass loss compared to other glaciers in the sub-basin. Another key finding of the anomalous glacier dynamics study is the disintegrating behaviour of glaciers, which is also identified by interpreting the responses of physical scattering mechanisms retrieved from glaciers using fully polarimetric ALOS-2/PALSAR-2. Warming temperatures are expected to cause glacier retreat and separation of tributary glaciers from the main glacier body. Melt water from tributary glaciers can further accelerate glacier flow and ice melt in lower part of glacier trunk. This can lead to formation of dead ice zones and disintegration of Himalayan glaciers, which are supported by numerous tributary glaciers. Therefore, we expect that the loss in glacier area due to warming will be larger than the present prediction, where mass loss is considered from conventional way.

中文翻译：

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使用 DInSAR 发现喜马拉雅西部部分 Chandra-Bhaga 子盆地冰川的异常动力学和崩解行为

摘要 冰川速度是了解冰川动力学、质量和健康状况的重要参数之一。了解冰川速度还有助于分析冰厚度、冰通量和质量平衡。此外，流域/子流域明智的研究有助于了解该地区的气候变化，而不是监测单个冰川。在目前的研究中，使用先进的陆地观测卫星 2/相控阵型 L 波段合成器，在印度喜马偕尔邦的 Lahaul-Spiti 地区，为整个 Chandra 和 Bhaga 子盆地生成冰川速度的空间分布Aperture Radar-2 (ALOS-2/PALSAR-2) 差分干涉测量对图像，时间间隔为 14 天。与 Bhaga 子盆地中的冰川相比，钱德拉子盆地中的冰川被发现具有较高的流速。局部坡度和冰厚总体上向终点减小，控制着山谷冰川的运动，并且观察到大多数冰川向终点/锋区的运动速率较低。然而，Bhaga 子盆地的一些冰川在其正面区域显示出加速运动。在这项工作中也研究了这种不规则行为，发现地形坡度和来自相邻冰川的融水流入是这些冰川出现这种行为的主要原因。因此，与子盆地中的其他冰川相比，它们容易加速质量损失。异常冰川动力学研究的另一个重要发现是冰川的崩解行为，这也可以通过使用完全极化的 ALOS-2/PALSAR-2 解释从冰川中检索到的物理散射机制的响应来确定。预计气温升高将导致冰川退缩和支流冰川与冰川主体分离。来自支流冰川的融水可以进一步加速冰川流动和冰川干下部的冰融化。这可能导致死冰区的形成和由众多支流冰川支撑的喜马拉雅冰川的解体。因此，我们预计冰川面积因变暖造成的损失将大于目前的预测，其中质量损失是按常规方式考虑的。来自支流冰川的融水可以进一步加速冰川流动和冰川干下部的冰融化。这可能导致死冰区的形成和由众多支流冰川支撑的喜马拉雅冰川的解体。因此，我们预计冰川面积因变暖造成的损失将大于目前的预测，其中质量损失是按常规方式考虑的。来自支流冰川的融水可以进一步加速冰川流动和冰川干下部的冰融化。这可能导致死冰区的形成和由众多支流冰川支撑的喜马拉雅冰川的解体。因此，我们预计冰川面积因变暖造成的损失将大于目前的预测，其中质量损失是按常规方式考虑的。