Due to the sensitivity of runoff to changes in seasonal snowpack, the changes in surface runoff within high-latitude and high-elevation areas are more complex than in other areas. However, this sensitivity is often overlooked when correlating changes in runoff with meteorological variables. Here, we analyze changes in surface runoff during snowmelt and snowless periods and their sensitivity to climate change from 1960 to 2019 in the upstream watersheds of the Songhua, Yalu, and Tumen Rivers in Changbai Mountain. Most runoff indices, except for low flow in the Yalu River, exhibited decreasing trends during snowmelt and snowless periods. Precipitation was the primary variable responsible for surface runoff during snowless and snowmelt periods. Notably, rainfall replenished all runoff indices during snowless periods, particularly under high flow conditions. The average and high flows were also primarily supplemented by rainfall during snowmelt periods. However, low flow was positively correlated with snowmelt in the Songhua and Tumen Rivers and with temperature in the Songhua, Yalu and Tumen Rivers during snowmelt periods. Additionally, extreme runoff events were closely associated with extreme precipitation. These findings demonstrate the seasonal and index-dependent climate sensitivity of surface runoff within Changbai Mountain, offering insights into the surface runoff response mechanism to climate change in high-altitude mountainous areas. Under future climate change conditions, frequent and intense extreme precipitation events may increase the risk of flooding, owing to the high sensitivity of high flows to precipitation, posing a serious threat to regional ecological security.

中文翻译：

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长白山主要河流表层径流的季节依赖性气候敏感性


由于径流对季节性积雪变化的敏感性，高纬度和高海拔地区地表径流的变化比其他地区更复杂。然而，在将径流变化与气象变量相关联时，这种敏感性经常被忽视。本文分析了 1960 年至 2019 年长白山松花江、鸭绿江和图们江上游流域融雪和无雪期地表径流的变化及其对气候变化的敏感性。除鸭绿江低流量外，大多数径流指数在融雪期和无雪期均呈下降趋势。降水是导致无雪和融雪期间地表径流的主要变量。值得注意的是，在无雪期间，降雨补充了所有径流指数，尤其是在高流量条件下。平均和高流量也主要由融雪期间的降雨补充。然而，在融雪期间，低流量与松花江和图们江的融雪以及松花江、鸭绿江和图们江的温度呈正相关。此外，极端径流事件与极端降水密切相关。这些发现证明了长白山地表径流的季节和指数依赖性气候敏感性，为高海拔山区地表径流对气候变化的响应机制提供了见解。在未来气候变化条件下，由于高流量对降水的高度敏感性，频繁而强烈的极端降水事件可能会增加洪涝风险，对区域生态安全构成严重威胁。