重庆主城区近百余年降水的变化特征

The Characteristics of Variation in Precipitation in Chongqing Urban Area During the Past 100 Years

利用1892—2009年重庆主城区降水资料,采用多种统计方法,分析了近百余年来重庆主城区年和四季降水的气候变化特征.结果表明:重庆市主城区近百余年来,年、春季、夏季和冬季降水线性变化趋势都不明显,都为略增多的趋势.秋季降水为显著的减少趋势,减少率为-6.7mm/10a,通过了0.01的水平置信度检验.年和四季降水的阶段性变化差异明显.年降水在近百余年未发生明显的突变.春季、夏季和冬季降水都发生过一次突变,分别发生于1915、1978、1956年,都突变为增加趋势.秋季降水第一次突变发生于1963年,突变为增加趋势;第二次突变发生于1974年,突变为减少趋势.周期分析表明近百余年来年降水存在3a左右的显著周期,春季降水存在7a和5a左右的显著周期,夏季降水存在3a和6a左右的显著周期,秋季降水存在2a左右的显著周期,冬季降水存在3a左右的显著周期.

On the basis of the precipitation data in Chongqing urban area from 1892 to 2009, characteristics of the local annual and seasonal precipitation variation were analyzed with different statistical methods. The main results showed that the annual, spring, summer, and winter precipitation in Chongqing urban area all showed a weak increasing trend during the past 100 years, and autumn precipitation showed a highly significant decreasing trend （r≤ 0.01）. Stage changes of annual and seasonal precipitation were significantly different. Annual precipitation had no obvious sudden change during the past 100 years. Sud- den increase in spring, summer and winter precipitation occurred once each, in 1915, 1978 and 1956, re spectively. A sudden increase in autumn precipitation occurred in 1963, and a sudden decrease in autumn precipitation occurred in 1974. In a period analysis, periodic oscillations were observed, about 3a for annu- al precipitation, 7a and 5a for spring precipitation, 3a and 6a for summer precipitation, 2a for autumn precipitation and 3a for winter precipitation.