为掌握南水北调中线工程沿线寒潮及区域极端低温时空变化规律，基于南水北调中线工程陶岔渠首至北拒 马河暗渠沿线 40?km 宽度范围内的 56 个气象站点 1960—2020 年日最低、最高气温数据资料，分析 5 个极端气候 指数时空变化规律，另外计算 9 个典型气象站 1960—2020 年寒潮发生频次，采用 Sen 斜率估计方法进一步分析 其变化趋势。结果表明：9 个典型气象站中，1960—2020 年 7 个气象站寒潮发生频次总体呈减少趋势；2 个气象站 寒潮发生频次总体呈下降趋势，但 2000 年以来呈现明显增多的异常趋势；邢台以北区域随纬度升高寒潮呈增多 趋势。对于极端气候指数 1960—2020 年 9 个气象站每年度日最低气温的最小值总体均呈现上升趋势，但 1990 年 以来保定站呈现不升反降的异常趋势，邢台、石家庄两站也基本不再上升，处于上升停滞状态；霜冻日数（每年度 日最低气温<0℃ 的天数）、冰冻日数（每年度日最高气温<0℃ 的天数）、冷夜（最低气温<10% 分位值的天数）等极 端气候指数总体呈现不同的下降趋势，但邢台以北等站点也呈现不降反升或者下降停滞的异常状态。从空间变 化趋势上来看，各气候指数相互之间未呈现整体上一致性的变化规律，冰冻日数沿南水北调中线从南到北下降速 率总体呈加快趋势。

In cold regions, such as high latitudes during winter, rivers and water conveyance channels often experience the phenomenon of freezing under low temperature conditions. During the initial stage of freezing and the subsequent melting stage, ice floes are prone to get stuck in the channels, forming ice jams and dams, which obstruct the flow of water and raise the water level in the channels, thus adversely affecting winter water transfer. Cold waves and extreme low temperatures in the region often cause significant temperature fluctuations, which are the main factors influencing changes in the ice conditions of rivers and channels. The Middle Route of South-to-North Water Transfers Project (MRSWTP) spans multiple latitudes, and the areas north of the Yellow River are affected by ice conditions to varying degrees every year during winter operations. Therefore, analyzing the spatiotemporal variations of cold waves and regional extreme low temperatures along the MRSWTP is of great significance for ice disaster prevention, winter water transportation scheduling, and other related issues.Based on the daily minimum and maximum air temperature data of meteorological stations within a width of 40 km along the route from the head of Taocha Drainage Canal to the Beijuma Culvert of the MRSWTP from 1960 to 2020, the occurrences of cold waves and five extreme cold climate indices were calculated. The Sen’s slope estimator method was employed to analyze their trends. Additionally, the spatial variations of the five extreme climate indices were analyzed using the inverse distance weighting spatial interpolation method based on temperature data from 56 meteorological stations.The results show that among the nine typical weather stations selected, the frequency of cold waves in seven weather stations decreased from 1960 to 2020. The frequency of cold waves in Anyang and Baoding stations showed a downward trend, but since 2000, the number of cold waves has increased significantly. January has the highest frequency of cold waves occurrences, followed by December, February, and November. The regions north of Xingtai show an increasing trend in cold waves occurrence with rising latitudes. As for the extreme climate indices, the minimum value of the annual minimum temperature at the nine meteorological stations generally exhibits an increasing trend from 1960 to 2020. However, since 1990, Baoding station has shown an abnormal trend of not increasing but rather decreasing, while Xingtai and Shijiazhuang stations have remained in a state of stagnation without further increase. The other four extreme climate indices, including frost days (the number of days with a daily minimum temperature below 0 ℃) and freeze days (the number of days with a daily maximum temperature below 0 ℃), generally exhibit different decreasing trends, but some stations show abnormal trends of not decreasing but instead increasing or stagnating. Moreover, it is found that the decline rate of the number of days with a daily minimum temperature below 0 ℃ is faster compared to the decline rate of the number of days with a daily maximum temperature below 0 ℃, indicating a more significant impact of climate change. There is no consistent trend detected among the various climate indices in terms of spatial changes. For freeze days, the decline rate along the MRSWTP from south to north shows an accelerating trend.Under the overall trend of global climate warming, the frequencies of cold waves and extreme low-temperature weather along most regions of the MRSWTP have been slowing down, but there have been obvious intensifications observed in some regions since the 21st century. The winter water conveyance flow rate of the project will be further increased to meet the water demands for production, living, and ecology in northern cities. In future winter high-flow water conveyance plans, the impacts of severe cold waves and extreme low temperatures on winter water conveyance should be considered to reduce the risk of ice disasters.