【摘要】 根据1951—1980年资料分析发现,长江上游宜昌站9月和10月的径流量变化与华西秋雨的变化有密切关系。因此,有可能利用宜昌站1882—1980年的流量资料来研究华西秋雨近百年的变化。 分析结果表明,华西秋雨的多年变化具有明显的周期性和阶段性:9月的主要周期约为3年和17年,10月则约为13年。并按照正、负距平的分布特点,将9月划分为8个阶段、10月划分为9个阶段。这些阶段的出现与大气环流的变化有关;9月份与西太平洋高压脊西伸位置有关,10月则与印度低压的强弱相联系。更多还原

【Abstract】 It is found in this paper that the variations of runoff from the hydrome-tric station, Yichang, in the upper reaches of the Changjiang river in September and October reflect the variations of autumn rain in South-west China, Therefore, it is possible to utilize the data of runoff from the period 1882-1980 at Yichang to research into the fluctuation of autumn rain in Southwest China.The fluctuations of autumn rain in this region have cyclic character, the major cycle in September is about 3 year and 17 year, but it is about 13 year in October. The fluctuations of the autumn rain may be divided into many spells, some of them are above normal, but other are below normal. These spells are related with the condition of subtropical ridge in pacific in September and with Indian low in October更多还原