1981-2015年中国95°E以东区域性暴雨过程时、空分布特征

基于1981-2015年中国逐日降水量加密观测资料和NCEP/NCAR再分析资料，采用主、客观相结合的方法，以天气过程为单元建立了中国95°E以东地区及其6个子区的区域性暴雨过程个例谱，进一步使用小波功率谱、9点二项式平滑及离差平方和聚类等方法剖析了中国95°E以东区域性暴雨过程的时、空分布统计特征。结果表明:（1）中国95°E以东区域性暴雨过程平均年总次数接近30次；其中，江淮流域是出现区域性暴雨过程最多的子区，平均为19次/a；其次为华南和西南地区东部，平均为10.5和5.8次/a；东北地区、华北和西北地区东部平均仅为1-3次/a。（2）中国95°E以东及各子区区域性暴雨过程次数的年及年代际变化主要表现为波动特征，各子区中江淮流域与中国95°E以东地区的年及年代际波动变化最为一致；华南与西南地区、东北地区与华北的波动变化互为显著的正相关。中国95°E以东及各子区区域性暴雨过程年总次数都表现出2-4 a的周期变化，此外，江淮流域、华南和西北地区东部还表现出6-10 a的周期变化，华北表现出13-17 a的周期变化。（3）中国95°E以东区域性暴雨过程总体呈夏季最多、冬季最少、春季多于秋季的分布特征，其中以7月出现次数最多。各子区中，江淮流域和西南地区东部区域性暴雨过程以6、7月最多，华南以5、6月最多；东北地区、华北、西北地区东部集中出现在7、8月。（4）中国95°E以东地区的极端区域性暴雨过程可划分为7种分布类型。第Ⅰ-Ⅳ型强降雨区从江南南部和华南呈阶梯状逐步北抬至黄淮和四川盆地东部一带，第Ⅴ-Ⅶ型除在东南沿海均有强降雨区外，第Ⅴ型在华南东部至江淮、第Ⅵ型在黄淮北部至东北地区中南部、第Ⅶ型在黄淮西部和华北中南部还分布有强降雨区。 

Characteristics of temporal and spatial distribution of regional rainstorm processes to the east of 95°E in China during 1981-2015

The events of the regional rainstorm processes (RRP) to the east of 95°E in China over 1981-2015 are constructed based on intensive daily observations of precipitation in China and NCEP/NCAR reanalysis data by means of subjective and objective analyses. Temporal and spatial characteristic distribution of RRP in China are further investigated using the methods of wavelet power spectrum, nine-point binomial smoothing and Ward cluster analysis. The main conclusions are as follows. (1) The annual average number of RRP to the east of 95°E in China is nearly 30. RRP in the Yangtze-Huaihe River valley occur most frequently among the six subareas with an annual average number of about 19, followed by that in South China and eastern part of Southwest China with annual average numbers of 10.5 and 5.8 times respectively. Annual average number of RRP is only about 1-3 in other subareas. (2) The inter-annual and inter-decadal variations of the annual number of RRP exhibit distinct fluctuation characteristics. The inter-annual and inter-decadal fluctuating variation in the Yangtze-Huaihe River valley is the most consistent with that to the east of 95°E in China. Moreover, the fluctuating variations have a significant positive correlation between South China and eastern part of Southwest China, and also between Northeast China and North China. The annual number of RRP over the east of 95°E in China and its subareas demonstrates a periodic variation of 2-4 a, and also a periodic variation of 6-10 a in the Yangtze-Huaihe River valley, South China and eastern part of Northwest China, while a 13-17 a oscillation can be found in North China. (3) On the whole, the occurrence frequency of RRP to the east of 95°E in China is the most in summer (especially in July), the least in winter, and higher in spring than in autumn. The months when RRP occur most frequently are June and July in the Yangtze-Huaihe River valley and eastern part of Southwest China, and May and June in South China. RRP mainly appear in July and August in other subareas. (4) The distribution pattern of RRP to the east of 95°E in China are divided into 7 types. The heavy precipitation areas for pattern Ⅰ-Ⅳ migrate northward step by step from South China and southern part of Yangtze River valley to Huanghuai Basin and eastern part of Sichuan Basin. The heavy precipitation areas of pattern Ⅴ-Ⅶ all are located at the coastal region of Southeast China, moreover precipitation of pattern Ⅴ are concentrated from the eastern part of South China to Huaihe River, and precipitation of pattern Ⅵ are located from the northern part of Huanghuai Basin to central-southern part of Northeast China, precipitation of pattern Ⅶ are concentrated over the western part of Huanghuai Basin and central-southern part of North China.