长江中下游梅雨量与西北地区东部夏季降水的联系

应用1951—2000年长江中下游梅雨量资料及全国160个站1951—2000年历年降水量资料,分析了长江中下游梅雨量与西北地区东部夏季降水量之间的联系。结果表明：梅雨量偏多年份,西北地区东部夏季降水正常或偏旱;梅雨量偏少年份,西北地区东部夏季降水偏多。梅雨特多(少)的合成流型与西北地区东部特征的干旱(多雨)流型相对应。并用MM5模式数值研究了多(少)梅雨年500hPa高度场演变的不同特征及其与西北地区东部降水的联系。

Relationship between Precipitation for Meiyu in Mid-and-Lower Reaches of the Yangtze River and Summer Precipitation over Eastern Part of Northwest China

Using the Meiyu data in the mid-and-lower reaches of Yangtze River in the period from 1951 to 2000, the precipitation at 160 stations during 1951 to 2000 and the NCEP reanalysis data, the relationship between the precipitation for Meiyu in the mid-and-lower reaches of Yangtze River and the summer precipitation on the eastern side of the Northwest China was analyzed. The results show that, in the years of more precipitation for Meiyu, the summmer precipitation in the eastern part of the Northwest China is normal or drought; but in the years of less precipitation for Meiyu, vice versa. The composite flow pattern of the most (least) precipitation for Meiyu years is corresponding to the typical flow pattern for drought (rainy) years in the east of Northwest China. The different featares of 500 hPa height field in more(less) Meiyu years and its relation to the precipitation in east of Northwest China are numerically simulated by using the norhydrostatic version MM5 with one nested grid.