西安市秋雨气候特征及预测

Analysis and Forecasting on the Weather of Autumn Rain in Xi'an

利用1961—2014年西安市7个区县地面气象观测站8月21日—10月31日的逐日降水量和国家气候中心提供的74项环流特征量资料,采用线性倾向估计、滑动t检验、Mann-Kendal、Morlet小波及相关分析方法,分析了西安秋雨的变化趋势、变化周期、气候突变和气候响应,研究了西安秋雨与前期环流特征量间的相关关系,并建立了秋雨预测模型.结果表明,1961—2014年西安秋雨呈线性减少趋势,其中1961—1985年为偏多时段,1986—1999年为偏少时段,2000年以来又趋向偏多.秋雨存在显著的2年、4~8年的变化周期以及24年的长周期震荡,在20世纪80年代中期和60年代、90年代末期发生了突变.秋雨强度指数与厄尔尼诺/拉尼娜气候事件年有很好的对应关系,厄尔尼诺事件对应的是秋雨偏弱,拉尼娜事件对应的是秋雨偏强.秋雨量偏少/多的气候背景下发生厄尔尼诺/拉尼娜气候事件,其秋雨强度指数偏弱的可能性极大/较小.

We based on the daily precipitation data of seven countries meteorological stations in Xi’an of August 21 to October 31 and 74 circulation characteristics of the national climate center from 1961-2014,used the statistical diagnostic methods such as linear trend analysis,moving t-test,Mann-Kendal,Morlet wavelet and correlation analysis methods,analyzed the change trend of autumn rain,change periods,climate abrupt change and climate response in Xi’an,studied the correlation of autumn rain in Xi’an between the prophase circulation characteristics,and established the autumn rain forecasting model. The results showed that in 1961 to 2014,the autumn rain in Xi’an had decreased linearly. The autumn rain were more than normal in 1961 to 1985 and 2000 to 2014 and less than normal in 1986 to 1999. The autumn rain change cycle of 2 years and 4 to 8 years and the long period oscillation for 24 years were fonnd,and the abrupt changes occurred in 1986 and 2000. The fall rain intensity index had a good correlation with the El Nino/La Nina year of climate events,and the El Nino event was corresponded to a decline in autumn rain,and the La Nina event was corresponded to an increase in autumn rainfall. El Nino/La Nina weather event in the context of a climate with less rainfall than the rainfall was likely to be very small.