干旱条件下吐鲁番盆地相对湿润指数变化特征分析

利用干旱条件下的吐鲁番盆地1981-2010年的逐月降水、气温资料，通过Thornthwaite方法计算潜在蒸散量确定气候相对湿润指数，并分析其时空变化特征；同时应用小波分析及Mann-Kendall法，对相对湿润指数进行突变和周期分析，结果表明：近30 a来，降水量呈非显著性的减少趋势，气温增暖趋势明显，倾向率为0.53益·（10 a）-1；在气候变暖的背景下，潜在蒸散量呈波动增加趋势，空间分布差异显著（P〈0.05）；相对湿润指数呈较弱的减小态势，气候总体趋于干旱化，表现为：鄯善最强，吐鲁番次之，托克逊相对较弱；相对湿润指数未出现显著的转折年份和突变时间区域；周期变化表现为较强的对称性，4～5a的变化周期一致性较好。研究区域内气温升高，降水减少，是导致气候干旱化趋势得以维持和加剧的重要因素。

Analysis on variation characteristics of relative moisture index in Turpan basin under arid condition over recent 30 years

The relative moisture index was calculated with the potential evaporation by using Thornthwaite method, which was based on the monthly temperature and precipitation data at Turpan basin during 1981-2010. The relative moisture index changes were studied by using Mann-Kendall and Morlet wavelet method. The results showed that precipitation had a non-remarkablely decrease tendency , but the rising of temperature was obvious, and the increasing rate of that was 0.53 ℃· （10a）-1;potential evapotranspiration had an ascent trend that was wave-like increases with a significant difference in spatial distribution （P〈0.05） under the background of global warming. Further analysis indicated that the relative moisture index had a weak decreases and the climate tended to arid which presented Shan-shan as the most arid ,followed by Turpan and Tuksun. In a considerable degree, it reflected that 4~5 years of oscillatory cycle had obvious consistency oscillations and no catastrophe for that. The analyses showed that temperature rising and precipitation decreasing were important factors for the maintenance and aggravation of arid climate .