1951-2012年江淮流域夏季降水指数数据集

根据江淮流域23个台站（新浦、清江、蚌埠、阜阳、信阳、东台、南京、合肥、上海、杭州、安庆、屯溪、九江、汉口、钟祥、岳阳、宜昌、常德、宁波、衢县、贵溪、南昌、长沙）夏季降水距平百分率资料，首先利用EOF分析方法获得该区域的两个主要模态（EOF1和EOF2），然后分别针对模态1和模态2，计算与模态同号的夏季降水距平百分率的累加量的绝对值和异号的夏季降水距平百分率累加量的绝对值的差值并除以总台站数23，即得到每一年各模态的降水指数，将两个模态降水指数绝对值大的作为这一年的主要旱涝型，而指数的正负则分别对应着该模态的正位相和负位相。时间分辨率为：逐年。数据精度1%。数据集每年更新一次。

Based on the summer precipitation anomaly percentage data from 23 meteorological stations (Xinpu, Qingjiang, Bengbu, Fuyang, Xinyang, Dongtai, Nanjing, Hefei, Shanghai, Hangzhou, Anqing, Tunxi, Jiujiang, Hankou, Zhongxiang, Yueyang, Yichang, Changde, Ningbo, Quxian, Guixi, Nanchang, Changsha) in the Jianghuai River Basin, this dataset first adopts Empirical Orthogonal Function (EOF) analysis to derive the two dominant modes (EOF1 and EOF2) of the region. For each of the two modes, the precipitation index of each year is calculated as follows: compute the difference between the absolute value of the cumulative summer precipitation anomaly percentages with the same sign as the mode and the absolute value of the cumulative summer precipitation anomaly percentages with the opposite sign, then divide the resulting difference by the total number of stations (23). The mode with the larger absolute value of the two precipitation indices is designated as the primary drought-flood pattern for that year, while the positive and negative values of the selected index correspond to the positive and negative phases of the respective mode, respectively. The temporal resolution of this dataset is annual, with a data accuracy of 1%, and it is updated once per year.