新疆阿勒泰地区冬季极端低温事件特征分析

Variation of Extremely Low Temperature Events in Winter of Aletai Region

利用阿勒泰地区7个测站1961～2011年冬季(11月到翌年3月)逐日最低温度资料,采用百分位定义法给出各站发生冬季极端低温事件的阈值。采用气候趋势系数和气候倾向率、Gumbel分布函数及R/S分析等多种统计方法分析阿勒泰地区各站冬季极端低温事件的气候特征。结果表明:阿勒泰地区各站冬季极端低温事件发生阈值为-26～-36℃。阿勒泰地区冬季极端低温事件频次倾向率均呈减少趋势,强度倾向率均呈减弱趋势。50 a一遇冬季极端低温事件极值东部较低,西部较高。阿勒泰地区西部地区冬季极端低温强度<-50℃的概率较小,东部地区冬季极端低温事件强度<-50℃概率较大。根据R/S分析,阿勒泰地区冬季极端低温事件未来发生频次可能会有所增多,冬季极端低温事件未来发生强度可能会有所增强。

Based on the daily minimum temperature in winter（from November to March）during 1961-2011 at seven stations in Aletai region,the threshold of extremely low temperature at each station was given by using percentile method definition,and the climatic features of extremely low temperature events in winter of Aletai region were analyzed by using the methods of climate tendency coefficient,climatic trend rate,Gumbel function and R/S analysis.The results show that the threshold of the extremely cold events in winter at each station ranged from-26 to-36 ℃,and the frequency tendency rate and intensity of extremely cold events decreased in recent years.The extremely minimum temperature value which encounterd in 50 years was lower in the eastern region and higher in the west region,and the probability of extremely low temperature less than-50 ℃ was smaller in west region and higher in east region of Aletai.According to the R/S analysis,the extremely cold events in winter may increase and the intensity may be enhanced in Aletai region in future.