Assessment of the response of the Himalayan river flows to climate change is complex due to multiple contributors: rainfall, snowmelt, and glacier‐melt. The number of studies is limited in this direction due to lack of data availability as well as non‐availability of models considering all the above‐mentioned components. As for example, the state‐of‐the‐art variable infiltration capacity (VIC) model does not account for the glacier melt. Here we integrate a glacier‐melt model with VIC and validate the model output with observed streamflow in five river basins in the Himalayas, at daily scale. Our model simulates the streamflow with Nash‐Sutcliffe estimates greater than 0.65 in all basins. The sensitivity analysis shows that the contribution from snowmelt decreases substantially in all the five basins with highest decrease of 36% in Dudh Kosi (DK), in a warm and dry scenario. The glacier‐melt increases (15%–70%) in a warmer environment with its present volume, but decreases (3%–38%) substantially, when the volumes are reduced to half. However, such a decrease is found to be compensated by increased precipitation in a wetter scenario with a net increase of 3%–13%. Climate model simulations show a decrease in the spring onset times for Sutlej basin while increase for DK basin for both RCP4.5 and RCP8.5 scenarios. Sutlej and Arun basins show decreases of more than 6 days in the center of volume of streamflow, which suggests that there will be increased flows in the early part of year and reduced flows later in the year.

中文翻译：

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气候变化中的喜马拉雅河流量组成

喜马拉雅河流域对气候变化的响应的评估是复杂的，这有多种原因：降雨，融雪和冰川融化。由于缺乏数据可用性以及考虑到上述所有因素的模型的不可用性，研究数量在这个方向上受到限制。例如，最新的可变渗透能力（VIC）模型不能解决冰川融化的问题。在这里，我们将冰川融化模型与VIC集成在一起，并通过每天在喜马拉雅山的五个流域观察到的水流来验证模型输出。我们的模型在所有流域中使用Nash-Sutcliffe估计值大于0.65来模拟水流。敏感性分析表明，在所有五个盆地中，融雪的贡献均显着下降，其中Dudh Kosi（DK）的降幅最大，达36％，在温暖干燥的环境中。在较温暖的环境中，冰川融化物的体积增加了（15％–70％），但是当体积减少一半时，冰川融化量却大大减少（3％–38％）。但是，在较湿的情况下，这种减少被降水增加所补偿，净增加了3％–13％。气候模型模拟表明，对于RCP4.5和RCP8.5情景，Sutlej盆地的春季发病时间减少，而DK盆地的春季发病时间增加。Sutlej和Arun盆地的水流中心位置减少了6天以上，这表明年初流量会增加，而今年晚些时候流量会减少。当音量减小到一半时。但是，在较湿的情况下，这种减少被降水增加所补偿，净增加了3％–13％。气候模型模拟表明，对于RCP4.5和RCP8.5情景，Sutlej盆地的春季发病时间减少，而DK盆地的春季发病时间增加。Sutlej和Arun盆地的水流中心位置减少了6天以上，这表明年初流量会增加，而今年晚些时候流量会减少。当音量减小到一半时。但是，在较湿的情况下，这种减少被降水增加所补偿，净增加了3％–13％。气候模型模拟表明，对于RCP4.5和RCP8.5情景，Sutlej盆地的春季发病时间减少，而DK盆地的春季发病时间增加。Sutlej和Arun盆地的水流中心位置减少了6天以上，这表明年初流量会增加，而今年晚些时候流量会减少。