甘肃空中水汽含量演变特征

为揭示甘肃空中水汽的时空演变,采用EOF、REOF、小波分析和计算Petitt变点等方法,研究了该区域大气中水汽含量在近40 a的变化.结果表明：甘肃水汽变化存在4个敏感区（空间型）,东部、西部是最敏感地区,中部敏感程度次之;在时间变化上阶段性明显,1977、1987年发生突变,1977年之前呈明显下降趋势,1977～1987年间波动,1987年后呈明显上升趋势;小波分析表明水汽变化存在2～4 a为主的振荡,20世纪70年代以前变幅大,80年代以后变幅小.

Evolution and Abrupt Change of Atmospheric Water Vapor over Gansu Province

To reveal the characteristics of the spatial-temporal variations of water vapor over Gansu Province,the variation of the atmospheric water vapor content over the area from 1961 to 2000 was studied by means of EOF,REOF,wavelet and Petitt jump-point methods.The results show that there were four sensitive areas(spatial pattern) in water vapor variation in Gansu: the eastern and western parts are the most sensitive;the central part is the second;the temporal variation show obviously phasic feature.Abrupt changes occurred in 1977 and 1977: there were a decreasing trend before 1977,fluctuation in 1977-1987,an obvious increasing trend after 1987.The wavelet analysis indicates that there was remarkable oscillation in water vapor with the periods being 2 to 4 years,strong in variability before the 1970s,relativity weak after the 1980s.