秦岭—淮河地区受复杂地形与多变季风气候影响，降水在年际和年内波动较大，空间分布呈明显区域性。本研究通过分析不同时间尺度降水量，年降水量丰平枯状态和相邻年份年降水量变化的增平减趋势，对秦岭—淮河地区进行了降水空间聚类。结果显示，表明：据候降水量指标可将秦岭—淮河地区分为江淮、黄淮、秦岭以南、秦岭以北4个区，据年降水量丰平枯状态联系数指标可将该地区分为江淮、黄淮、秦岭淮河交界附近、秦岭以北高原和秦岭以南西段4个区，据相邻年份年降水量变化增平减趋势联系数指标可将该地区分为江淮、黄淮、秦岭3个区；融合3个降水指标的区域划分结果，可将秦岭—淮河地区划分为6个区：江淮、黄淮、秦岭以南、秦岭以北西段和高原区、关中区、秦岭淮河交界过渡区。基于线性矩法的分区一致性检验表明分区内无奇异站点。

Affected by complex and diverse landforms, along with unstable monsoon climate, the precipitation in Qinling-Huaihe region not only varied greatly at both the inter- and intra-annual time scales, but also exhibited strong spatial variability. The precipitation amount and its variation showed strong regional characteristics over multi-year time scales, especially for multi-year annual precipitation. However, in the current research, the adopted study area for the spatial-temporal characteristics analysis of precipitation in Qinling-Huaihe region was completely identical to the administrative regions, or was directly bounded by Qinling Mountains or Huaihe River. Obviously, spatial variability of precipitation in Qinling-Huaihe region has not been fully reflected. In this study, three types of precipitation indexes were used to divide subregions of Qinling-Huaihe region with step-wise clustering method. They were multi-year average precipitation amount at different time scales, including multi-year average daily, pentadly, decadally, monthly, and yearly precipitation amount, the connection number of every two stations in terms of the abundant, normal, or dry state of annual precipitation at each site, and the connection number of every two stations based on the trends of annual precipitation change in adjacent years. Average and standard deviation analysis method was used to identify the abundant, normal, or dry state of annual precipitation at each site under the condition that each state had equal probability, and the method was also suitable to identify the increase, unchangeability, or decrease trend of annual precipitation change in adjacent years. Among the indexes of multi-year average precipitation amount at different time scales, the Qinling-Huaihe region can be divided into four subregions based on the pentad precipitation, namely the subregion between Yangtze and Huaihe, the subregion between Huanghe and Huaihe, the subregion north of Qinling Mountains, and the subregion south of the Qinling Mountains. With the connection number of stations based on the abundant, normal, or dry state of annual precipitation, the Qinling-Huaihe region could be divided into four subregions, namely the subregion between Yangtze and Huaihe with multi-year annual precipitation greater than 900 mm, the subregion between Huanghe and Huaihe with multi-year annual precipitation less than 900 mm, the subregion of Surrounding area near the junction of Qinling Mountains and Huaihe River, and the subregion containing Loess Plateau Region at the north of Qinling Mountains and west section at the south of the Qinling Mountains. Meanwhile, with the connection number of stations based on the increase, unchangeability, or decrease state of annual precipitation change in adjacent years, the Qinling-Huaihe region could be divided into three regions, namely the subregion between Yangtze and Huaihe, the subregion between Huanghe and Huaihe, and the subregion containing the south and north regions of the Qinling Mountains. Combining the subregion dividing results with the three precipitation indexes, the Qinling-Huaihe region could be spatially divided into six regions, i.e., five major subregions and one transitional subregion, namely, the subregion between Yangtze and Huaihe, the subregion between Huanghe and Huaihe, the subregion at the south of Qinling Mountains, the subregion of west section at the north of the Qinling Mountains and the loess Plateau Region at the north of Qinling Mountains, the subregion of Guanzhong Plain and its nearby regions, and the transitional region between Qinling and Huaihe River in north-south orientation. The discordancy measure test was carried out using the L-moment ratios approach, and the results showed that six subregions divided in this study could be considered as homogeneous regions.

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国家自然科学基金项目（面上项目，重点项目，重大项目）,国家重点研发计划项目,安徽省自然科学基金