1960-2012年陕西汉中地区极端气温指数变化特征

利用1960-2012年汉中地区每日气温资料,运用线性倾向估计方法、Mann-Kendall突变检验法、Morlet复数小波分析等方法,对汉中地区9种极端气温指数随时间的变化趋势、突变年份及周期性进行了研究.结果表明,1960-2012年汉中地区极端最低气温、极端最高气温、暖夜、暖日、夏天日数和热夜日数变化均呈上升趋势,而冷夜、冷日和霜日变化均呈下降趋势.其中,上升态势最显著的是暖夜、夏天日数和热夜日数,升幅分别为7.94、3.54、3.06d/10a;下降趋势最显著的是冷夜和霜日,降幅分别为5.83、5.14d/10a.除了热夜日数之外,各极端气温指数均呈现具有年代际阶段性变化特征,并有突变现象发生.极端气温突变主要发生在20世纪60年代、80年代中期、90年代后期、2000-2010年.汉中地区极端气温事件普遍存在30年左右的主周期,冷日和极端最高气温还具有17年左右的变化周期,冷日、冷夜、暖日和暖夜均具有更小尺度的周期.综合分析得出,目前该区正处于气温突变容易发生的阶段.1960-2012年汉中地区极端气温呈明显的升高趋势,这易于造成农业气象灾害,需要加强对气象灾害的预防.

Change of Extreme Temperature Index in Hanzhong Region in Shaanxi Province during 1960-2012

Using the daily temperature data of Hanzhong region from 1960 to 2012,the change trend,mutation year and periodicity of nine extreme temperature indices in Hanzhong region were studied by the method of linear trend,Mann-Kendall mutation test and Morlet complex wavelet analysis.The results showed that the extreme minimum temperature,extreme maximum temperature,warm night,warm day,summer day,hot night were on the rise in Hanzhong region during 1960-2012,while cold night,cold day and frost day were on the decline.Among that warm night,summer day,hot night had increased significantly,in rate of 7.94,3.54 and 3.06 d/10 a respectively.Cold night and frost day had an obvious decline,in rate of 5.83 and 5.14 d/10 a respectively.Except hot night,there were stages change characteristic for each extreme temperature index,also with mutation characteristic.The mutation of extreme temperature mainly happened in the 60′s,the middle of 80′s,the late of 90′s and 2000-2010.There was generally a main cycle around 30 years for extreme temperature events in Hanzhong region,there was a cycle around 17 years for cold day and extreme maximum temperature,there was a cycle of smaller scale than 17 years for cold day and cold night,warm day and warm night.Conclude from comprehensive analysis,this region is now on period that temperature mutation happened easily.The extreme temperature in Hanzhong region during 1960-2012 has increased obviously,it is easily to cause agricultural meteorological disasters,people should strengthen the prevention of meteorological disasters.