上海地区梅雨与前期冬、春季升温的关系

Analysis on Relationship between Meiyu Rainfall in Shanghai and Temperature Ascent from Winter (JF) to Spring

利用1951—2006年中国160个测站逐月平均气温和降水资料、上海地区梅雨量以及美国NCEP/NCAR的1951—2006年逐月再分析700 hPa风场资料,分析了上海地区梅雨量与前期冬、春季升温值的关系。结果表明,上海地区梅雨量与前期我国东部中纬度地区的冬、春季升温值有较好的反相关关系;异常梅雨与前期的冬、春季升温差异与前期700 hPa经向风场有关。当冬、春季中纬度地区（20°-30°N,100°-120°E）的经向风差偏大时,对应的东部地区冬、春季降水差偏多,同期冬、春季升温值偏低,后期上海地区梅雨异常多;当冬、春季中纬度地区的经向风差偏小时,对应的东部地区冬、春季降水差偏少,同期冬、春季升温值偏高,对应后期梅雨异常少。

Using the monthly temperature and precipitation data of 160 observation stations in China, Meiyu rainfall data in Shanghai as well as 700 hPa winds of NCEP/NCAR reanalysis data during 1951-- 2006, the relation between the Meiyu rainfall in Shanghai and the temperature ascent from winter （JF） to spring over the eastern China are analyzed. The results reveal that the Meiyu rainfall amount in Shanghai has a closely negative relation with the temperature ascent from winter （JF） to spring. Furthermore, the value of the temperature ascent corresponding to abnormal Meiyu is seemly associated with 700 hPa merid- ional-wind over the mid-latitude area （20°-30°N, 100°-120°E） during the same period. Namely, the abnormal increase of Meiyu rainfall amount tends to occur when the earlier difference of the meridional-wind gets larger, consequently, the difference of rainfall between spring and preceding-winter thus rise and the value of the temperature ascent declines, and vice versa.