厄尼诺时期中国东部地区天气特征

根据1951—1985年500百帕平均环流资料研究表明，在厄尼诺年中，副热带高压环流比非厄尼诺年的环流强且建立早，而且，在西太平洋和东亚地区，当500百帕上正环流差值维持时，将抑制该地区气旋性环流的发展；在厄尼诺年中，在中国东部沿海的渤海、黄海海域上，气旋及气旋性辐合流场出现的频数明显减少；根据西太平洋与南海台风的统计，在厄尼诺年南海台风出现的频数减少，而且在我国东南沿海登陆的台风可减少20%，登陆位置偏南。

The Synoptic Characters in the Eastern China During the El Nino Period

The results of analyzing the 500 hPa monthly average circulation during 1951—1985 show that the occurrence of subtropical high in the El Nino period is earlier and stronger than that in the non-El Nino period. When the positive difference value of 500 hPa geopotential height between the El Nino and non-El Nino periods maintained in the western Pacific and eastern Asia, it would be unfavorable for developing the cyclonic circulation. Also, in the El Nino period, the frequencies of the cyclone and the cyclonic convergence circulation occurred in the Yellow Sea and Bohai waters of the coast of eastern China would be evidently reduced. In addition, according to the statistical data of typhoons in western Pacific and South China Sea, the typhoon in South China Sea is of very rare occurrence during the El Nino event, and the number of landing typhoon in the coast of southeastern China is reduced by 20%. Also, the landing position is located towards the south.