Regional characters of the Meiyu in Jiangsu

An attempt is made to find the regional precipitation characteristics during the Meiyu period in Jiangsu province. Derived from layered cluster analysis, the Jiangsu province is divided into three regions: Region 1, the northern Huaihe Area; Region 2, regions along Huaihe River and between Huaihe River and Yangtze River; Region 3, regions along Yangtze River and the southern region of Jiangsu province. The dataset used consists of records of daily precipitation from 66 meteorological stations over Jiangsu province during 49 yr (1961-2009). Using Morlet wavelet, binomial moving average method and composite analysis, we found that: 1. the precipitation anomaly shows different inter-annual and inter-decadal characteristics in the three regions during the Meiyu period. The 2 yr and 4 yr oscillation cycle exhibits after the 1980s, and the 6 yr oscillation cycle exhibits in the late 1980s and the middle 1990s over the most area to the south of Huaihe River. While in the northern Huaihe Area, the oscillation cycles were 7 yr, 4 yr, and 3yr. Although precipitation anomaly is different from the regions, there is a strong positive correlation between precipitation index I in Jiangsu province and that in the 3 regions, respectively. Besides, the Region 2 and Region 3 showed the lowest correlation among those of different regions.