1991—2020年江苏省连阴雨特征与区域指数构建

利用江苏省70个县级气象基本站1991—2020年逐日降水、日照时数资料，筛选出不同等级的连阴雨事件，建立连阴雨事件库。分析了江苏省连阴雨事件的时空分布特征和典型连阴雨过程，构建了区域连阴雨指数。结果表明：1） 江苏省以强连阴雨事件为主，事件年均发生次数、日数和降水总量从北到南依次增多。2） 苏北、苏中、苏南地区连阴雨事件的年发生次数、日数和降水总量表现出较明显的年代际差异，年际波动从北到南逐渐增强。苏北地区的连阴雨事件集中于盛夏发生，苏中地区多发于初春和盛夏，苏南地区于春夏大部分时间均较为频繁，秋冬亦较常见。3） 综合考虑连阴雨事件发生日数、降水量以及事件分布面积，构建区域连阴雨指数，以反映某一区域的连阴雨强弱情况。该指数较好地反映了2020年苏北、苏中、苏南三地区的区域连阴雨过程和强度变化。

Characteristic of continuous rainfall events in Jiangsu Province from 1991 to 2020 and regional index construction

Based on the data of daily precipitation and sunshine duration in Jiangsu Province during 1991-2020, continuous rainfall events (CRE) at different levels were selected, a database of CRE was established, the spatial temporal characteristics of CRE and a typical event were analyzed , and a regional CRE index was constructed in Jiangsu. The results showed that: 1) Jiangsu Province was mainly characterized by strong CRE, with a spatial distribution pattern from north to south, an increase in the number of events and days, and an increase in the total annual rainfall of the events. 2) The CRE events showed significant interdecadal differences in frequency, duration and rainfall over the northern, central and southern part of Jiangsu, with increasing interannual fluctuations from north to south. The CRE in northern Jiangsu were concentrated in midsummer, while those in central Jiangsu occurred more frequently in early spring and midsummer. Southern Jiangsu was more frequent in most of spring and summer, and autumn and winter were also more common. 3) Considering the duration, the rainfall and the distribution area of CRE, a regional CRE index was defined to describe the CRE over some regions. The index well reflected the CRE temporal distribution and intensity over the northern, central and southern part of Jiangsu in 2020.