长江中下游地区梅雨期降水与全球500hPa环流的关系

本文利用 ECMWF的全球500hPa高度月平均资料分析了长江中下游地区梅雨 期（6、7月）降水与全球同期和前期环流的关系。结果表明，长江中下游地区梅雨期降水不仅与北半球，尤其是欧亚地区的环流有关，而且与南半球同期和前期环流亦存在相当程度的联系，特别是发现了当2月份南印度洋中高纬度地区经向环流发展时，长江中下游地区梅雨期降水容易偏多。此外，南极极涡的强度变化也与长江中下游地区梅雨存在某种程度联系。

Relationship between the Global Circulation at 500 hPa and Meiyu in Mid- and Low-Reaches of the Yangtze River

Relationship between Meiyu in mid- and low-reaches of the Yangtze River and global atmospheric circulation is investigated using ECMWF's geopotenhal height data. It is shown that Meiyu is associated not only with the circulation of the Northern Hemisphere (especially Eutssia), but also with the contemporaneous and previous circulation of the Southern Hemisphere to a high degree. It is found that if the meridional circulation develops in February over the mid- and high-latitudes of the South Indian ocean, there tends to be more rain during following Meiyu preiod in mid- and low-reaches of the Yangtze River. In addition, Meiyu is related to the intensity of the South Pole vortex to some degree.