【摘要】 利用西北干旱区49个气象站1961—2000年0 cm地温和气温月平均资料,采用逐级归并法、小波分析、经验正交函数(EOF)、旋转经验正交函数(REOF)方法,分析了西北干旱区地气温差的时空演变特征、气候突变和周期振荡。结果表明:西北干旱区地气温差可分为12月~2月、3月、4~6月、7~10月和11月5类,11月和12月~2月呈下降趋势,3月、4~6月和7~10月呈上升趋势,12月~2月下降幅度较大,4~6月上升幅度最大;地气温差受大尺度气候异常的影响,第一载荷向量反映了全区一致的性质;北疆区和内蒙区有异常变化存在;3月和11月的突变点为1977年,12月~2月、4~6月和7~10月的突变点为1981年;周期振荡主要以3~6年为主。更多还原

【Abstract】 The temporal-spatial evolution features,abrupt climate change and oscillatory period of the difference between land surface and air temperature(simply as the(Ts-Ta)) are analyzed by using the monthly surface temperature and air temperature of 49 weather stations(1961-2000) in the arid region in Northwest China(NWC),with hierarchical cluster analysis,wavelet analysis,EOF,REOF methods.The results show that(Ts-Ta) in the arid region in NWC can be divided into December~February,March,April~June,July~October and November;(Ts-Ta) reveals the tendency of descent in November and December~February.(Ts-Ta) reveals the tendency of ascent in March,April~June and July~October months;the tendency of descent is the maximum in December~February and the tendency of ascent is the biggest in April~June;(Ts-Ta) is influenced by the large-scale weather systems,the first loading vector reflects the main spatially-anomalous structure;the north of the Xinjiang and the Inner Mongolia area have the exceptionally change existence;the abrupt year in March and November months is in 1977;the abrupt year in December~February,April~June and July~October is in 1981;the periodic oscillation is mainly 3~6 years.更多还原