2007年上海地区“非典型梅雨”特征和成因探讨

The Characteristics and Causation Analysis of Non-typical Meiyu of Shanghai in 2007

本文通过对2007年梅雨天气进行综合分析,指出近年来上海地区梅雨形势具有比较明显的非典型特征,即表现不是以连绵阴雨为主的常见特征,而是以过程性降水、高温和强雷雨天气等为主的特征,并认为鄂霍次克海阻高减弱、大陆高压脊活跃和西太平洋副高不稳定等是形成非典型梅雨的主要原因,还具体分析了梅雨期间过程性降水间转换机制和天气形势更替变化之间的关系。

This paper discussed some obviously non-typical characteristics of Meiyu in Shanghai area by the composite analysis of Meiyu weather in 2007.It showed that there had not been long-run rain but with process precipitation,high air temperature and severe thunderstorm weather.It was concluded that the weakening of Okhotsk Blocking high,strengthening of continent ridge and instability of western Pacific subtropical high were the main causes.The mechanism for the transformation of process precipitation and weather conditions were also analyzed.