武汉市近56 a梅雨期暴雨气候变化特征

Climate Change Characteristics of Rainstorm during the Meiyu Period in Wuhan City in Recent 56 Years

摘要: 本文利用1960~2015年武汉区域内5个国家级观测站逐日降水观测资料，以武汉区域气候中心按照最新标准修订的湖北省梅雨期时间为标准定义武汉市梅雨期，据此研究武汉市梅雨期暴雨的气候特征。主要研究方法为线性趋势、滑动平均、Morlet小波分析和Mann-Kendall突变检验等。结果表明：1) 武汉市梅雨期暴雨日数及暴雨量变化特征基本一致；梅雨期暴雨出现在6月下旬的次数最多。梅雨期暴雨量存在较大的年际变化，尤其进入90年代后年际振荡幅度增大，90年代后期暴雨量偏多趋势明显。极大值出现在1991年。2) 武汉市暴雨贡献率多年平均值为45.6%，峰值出现在2005年，达99.2%，谷值现在1965、1971、1977年，没有出现暴雨过程。3) 武汉市梅雨期暴雨总量80年代前后的增多是一次突变现象，具体是从1979年开始的。4) 武汉市梅雨期暴雨总量异常的振荡周期变化在56年中以准12 a为主；其次是7 a左右的周期。另外从80年代末中期开始存在4 a左右的短周期。

Abstract: In this article, we study the climate change characteristics of rainstorm in Wuhan’s Meiyu period, by using the precipitation data from five national meteorological observation stations in Wuhan, and the definition of Meiyu period which is revised by Wuhan regional climate center. Meanwhile, the main methods of this research are the trend analysis, moving average, Mann-Kendall test and Morlet wavelet analysis. Main results are: 1) The variation characteristics of heavy rain days and heavy rainfall in Wuhan’s Meiyu period are similar. The rainstorm happened the most in late June, and then in early July and mid-July, the least in late May. The amount of precipitation for rainstorm in Meiyu period varies annually: the oscillation amplitude increased especially in late 1990s; the amount of precipitation in late 1990s is obviously larger than that in early 1990s. And the maxi-mum value of precipitation happened in 1991. 2) In Wuhan, the rainstorm in Meiyu period’s aver-age rate of contribution for the whole precipitation is 45.6%. The peak of the rate appeared in 2005, which is 99.2%, and the valleys of the rate appeared in 1965, 1971 and 1977, which is zero. Such rate is well corresponding to the amount of precipitation in Meiyu period. 3) An increase of total rainfall for the rainstorm in Wuhan’s Meiyu period around 1980s is a mutant phenomenon. Specifically, it began in 1979. 4) The abnormal change of the period of oscillation for total rainfall for the rainstorm in Wuhan’s Meiyu period in 56 years is mainly 12 a, secondly 7 a. Furthermore, a short period of 4 a appeared in mid-1980s.