近140年芜湖地区降水量年代际变化特征

Interdecadal Variability of Precipitation in Wuhu in Last 140 Years

近百年来,全球气候发生了明显的年代际变化,探讨长江中下游地区代表站的百年降水变迁具有十分重要的意义。利用近140年芜湖市气象观测数据和最新发布的CRU降水资料,订正构建了1880—2019年芜湖市月降水量序列,并通过气候趋势、小波分析、MK检验、累积距平等方法分析了芜湖市百年降水变化特征。结果表明:近一个半世纪来芜湖市降水量呈现干、湿交替的分布。芜湖市年降水量存在40 a, 10 a, 5 a的周期,且呈微弱的增加趋势;春季降水量还存在80年的长周期变化,总体呈现减弱趋势;夏季降水量周期也与年降水量一致,增加趋势最为显著,对年降水量的增加贡献最大;秋、冬季降水量增加趋势并不显著,其周期变化也与春、夏季有所不同。19世纪90年代芜湖市各季降水量一致性偏少,20世纪初-1920年则异常偏多,这种各季变化高度一致性在百年芜湖市降水变化中非常罕见。1940年之后,各季节的年代际分布差异性逐渐增大,特别是近20年来各季降水量变化趋势的差异更为显著,冬季降水量在1997年以后呈明显上升趋势,春季降水量减弱趋势主要集中在2002年之后,秋季降水量则自2011年以后增加显著。

Global climate has significantly decadal change in the past century. Discussion on precipitation change of representative station in Middle and Lower Reaches of Yangtze River is meaningful. Based on precipitation observation data of Wuhu in last 140 years and CRU precipitation dataset, monthly precipitation series from 1880 to 2019 in Wuhu were corrected and constructed. Characteristics of precipitation series were analyzed through climate tendency, wavelet analysis, MK method and accumulative anomaly. The precipitation showed an alternate drying-wetting feature during the last one and a half centuries in Wuhu. Annual precipitation had quasi-forty, quasi-ten and quasi-five year periods and exhibited a weak increasing tendency in Wuhu. Spring precipitation had eighty-year period and displayed a decreasing trend. The period of summer precipitation was consistent with that of annual precipitation. Meanwhile, summer precipitation increased significantly and contributed most to annual precipitation. Autumn and winter precipitation showed no notable increasing tendency and their periods were different from those of spring and summer precipitation. Seasonal precipitation showed uniform less in the 1890 s and abnormal more in 1900 s and 1910 s. It was very rare that seasonal precipitation changes were completely consistent from 1890 s to 1910 s. The decadal variation differences between the seasonal precipitation increased gradually after 1940 s, especially in last twenty years. Winter precipitation showed the significantly increasing trend after 1997, while spring precipitation displayed the decreasing tendency after 2002 and autumn precipitation had increased obviously since 2011.