1961-2017年柴达木盆地干湿状况及其影响因子

根据1961—2017年柴达木盆地8个气象站数据资料,采用联合国粮农组织FAO推荐的Penman-Monteith模型计算潜在蒸散量,继而算得湿润指数,辅以气候倾向率、M-K检验、Morlet小波周期和主成分分析等方法,探究柴达木盆地干湿变化特征及影响因素。结果表明:1961—2017年,柴达木盆地整体具有变湿趋势,变化倾向率为0.007·(10a)~(-1)(α≥0.001),且湿润指数年际变化波动较大,变异系数为30.73%,春、夏、秋、冬四季湿润指数均呈上升趋势,倾向率分别为0.003·(10a)~(-1)、0.009·(10a)~(-1)、0.004·(10a)~(-1)、0.003·(10a)~(-1);空间变化差异显著,盆地东部地区变湿趋势大于西部,德令哈和都兰变湿趋势最为显著;湿润指数在1981年和1986年发生突变,且存在2.8 a和3.6 a(α≥0.05)的变化周期,与大气环流2～4 a周期较吻合;主成分分析表明,降水量和平均气温是柴达木盆地湿润指数的主要影响因子。此外,湿润指数与北半球极涡面积和强度及亚洲区极涡面积和强度关系密切,相关系数分别为-0.46、-0.36、-0.49、-0.47,均通过99%的显著性检验。

Surface Humid Situation and Its Affecting Factors in the Qaidam Basin from 1961 to 2017

The Penman-Monteithmodel was applied to estimate the values of evapotranspiration (ET0) in theQaidam Basin during the period of 1961-2017based on the meteorological data from 8 meteorological stations. Then the valuesof surface humid index were derived, and the climate tendency rate, IDWinterpolation, M-K test, Morlet wavelet and principal component analysis wereused to analyze the spatiotemporal variation of humid index and its affectingfactors in the study area. The results showed that the humid index in recent 57years was in an increase trend 0.007·(10a) ^-1, which revealed thatthe regional climate became wetter in the Qaidam Basin, the interannualvariation of the humid index was significant, and the variable coefficient was30.73%. Seasonally, the humid indexes in spring, summer, autumn and winter wereall in an increase trend, and the tendency rates were 0.003·(10a)^-1,0.009·(10a)^-1, 0.004·(10a)^-1 and 0.003·(10a)^-1 respectively. Spatially, difference of the variation was very significant, andthe increase of humid index in the eastern part of the basin was moresignificant than that in the western part. Mutation of humid index occurred in1981 and 1986, and there were 2.8-and3.6-yearperiods of humid index variation (α≥0.05), which was relatively identical withthe 2-4-year periodicity of general atmospheric circulation.Principal component analysis showed that precipitation and average temperature werethe main factors affecting the variation of humid index in the Qaidam Basin. Inaddition, the correlation coefficients between the humid index and the PVA,PVI, APVI and APVII were -0.46,-0.36,-0.49and -0.47(α≥0.01) respectively.