西北干旱区典型绿洲气候因子非线性特征研究——以新疆石河子地区为例

以西北干旱区典型绿洲新疆石河子地区为例，使用该区1959—2006年的年平均气温和降水量资料，基于小波变换从多时间尺度分析了气候因子的波动、突变和周期特性，并通过关联维数和R/S分析方法揭示了其分形与混沌特征。结果显示，石河子地区气候变化呈现复杂的非线性特征，具有分形、混沌特征和波动性。研究区降水量变化的主周期分别为5、8、14 a和20 a，但只有5 a和8 a通过了0.05水平下的显著性检验;温度变化的主周期分别在4、7 a和11 a，并且全部显著；研究区温度、降水量序列的关联维分别为4.51和3.21，均为非整数，这意味着该地区的气候因子具有分形和混沌特性；该区温度、降水量的饱和嵌入维分别为7和6，表明要对其进行系统动力学建模，分别需要5～7和4～6个独立的状态变量；在R/S分析中，根据研究区温度（1992—2006年）和降水量（1987—2006年）序列的Hurst指数预测，在2006年后的15 a内该区温度可能仍将保持上升趋势，而降水量在未来的20 a内将可能呈现轻微的下降趋势。

Nonlinear Characteristics of Climatic Factors in Oasis of Arid Northwest China: A case study of Shihezi, Xinjiang

Based on annual mean temperature and precipitation data during 1959—2006, the characteristics of climatic factors in Shihezi, a typical oasis in arid areas of northwest China, was researched through Morlet wavelet analysis, fractal analysis and R/S analysis. The results showed that the climatic variation of Shihezi presented a complex nonlinearity with waved, fractal and chaotic characteristics. The primary annual precipitation variation periods were 5, 8, 14, and 20 years, but only periods of 5 and 8 years were significant at P>0.05. The primary periods of annual mean temperature variation were 4, 7 and 11 years, and all these periods were significant at P>0.05. The correlative dimensions of annual mean temperature and annual precipitation series were 4.51 and 3.21 respectively, both were non-integral, indicating the fractal and chaotic variation processes of climatic factors. The embedding dimensions of annual mean temperature and annual precipitation were 7 and 6 respectively, which indicated that it needed 5~7 and 4~6 independent variables respectively to build systemic dynamic models. Based on the R/S analysis of annual mean temperature series (1992—2006) and annual precipitation series (1987—2006) of Shihezi, the Hurst exponents indicated that the annual mean temperature would keep an increasing trend in the coming 15 years after 2006, while the annual precipitation would keep a slightly decreasing trend in the coming 20 years.