Precipitation extremes and their underlying causes are important processes to understand to plan appropriate adaptation measures. This paper presents an analysis of the spatiotemporal variability and trend of precipitation extremes in the important source region of the Yellow River and explores the connection to global teleconnection patterns and the 850-mb vector wind. Six indices for precipitation extremes were computed and analyzed for assessment of a changing regional climate. Results showed that these indices have a strong gradient from the northwest to the southeast part for the period 1961–2015, due to the great influence from the south-easterly summer monsoon flow. However, no statistically significant trends were found for the defined indices at the majority of stations, and their spatial distribution are noticed by irregularly mixed positive and negative changes except for the maximum number of consecutive wet days (CWD). Singular value decomposition analysis revealed that the precipitation extreme indices—including annual total precipitation when daily precipitation >95th percentile (R95p), annual count of days with daily precipitation ≥10 mm (R10mm), annual maximum consecutive 5-day precipitation (R5d), total precipitation divided by the number of wet days (SDII), and CWD—are negatively related to the El Nino-Southern Oscillation (NINO 3.4) in the first mode, and the maximum number of consecutive dry days (CDD) is positively related to the Scandinavian pattern in the second mode at 0.05 significance level. The 850-mb vector wind analysis showed that the southwestern monsoon originating from the Indian Ocean brings sufficient moisture to this region. Furthermore, the anti-cyclone in the western part of the North Pacific plays a significant role in the transport of moisture to the source region of the Yellow River. The links between precipitation extremes and teleconnection patterns explored in this study are important for better prediction and preparedness of climatic extremes.

中文翻译：

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黄河源区降水极值变化及其与遥相关型的关系

降水极端事件及其根本原因是了解规划适当适应措施的重要过程。本文分析了黄河重要源区降水极端事件的时空变化和趋势，并探讨了与全球遥相关模式和 850-mb 矢量风的联系。计算和分析了六个极端降水指数，以评估不断变化的区域气候。结果表明，受东南夏季风气流影响较大，1961-2015年这些指数从西北向东南呈现强梯度。然而，在大多数站点的定义指数中没有发现具有统计意义的趋势，除了最大连续潮湿天数（CWD）外，它们的空间分布通过不规则混合的正负变化注意到。奇异值分解分析显示，降水极值指数——包括日降水量>95%时的年总降水量（R95p）、年日降水量≥10mm的天数（R10mm）、年最大连续5天降水量（R5d）、总降水量除以湿天数（SDII）和CWD——与厄尔尼诺-南方涛动（NINO 3.4）在第一模式下呈负相关，最大连续干天数（CDD）正相关于第二种模式中的斯堪的纳维亚模式，显着性水平为 0.05。850 mb 的矢量风分析表明，源自印度洋的西南季风为该地区带来了足够的水分。此外，北太平洋西部的反气旋在向黄河源区输送水分方面起着重要作用。本研究中探索的降水极端事件与遥相关模式之间的联系对于更好地预测和准备极端气候事件非常重要。