新疆潜在蒸散分形特征与R/S趋势分析

目的]分析新疆潜在蒸散的时间序列,判断时间序列的分形结构,对新疆潜在蒸散的变化趋势进行预测.方法]应用Penman-Monteith模型计算了新疆53个气象台站1955～2008年的潜在蒸散量时间序列,并采用配分函数(统计矩)判定该时间序列的分形结构,再利用重标极差分析法(R/S)对新疆潜在蒸散变化趋势进行预测.结果]配分函数τ(q)与q的线性关系非常明显,对于高阶q取值为10,20,…,100时也成立,依然有较好的线性关系.三个区域年平均潜在蒸散量时间序列存在明显的Hurst现象,Hurst指数分别为0.896 0、0.719 4、0.788 9.结论]南疆区、北疆区、天山山区1955～2008年潜在蒸散时间序列是一个单分形结构.新疆潜在蒸散变化存在着持续性.其中,南疆区潜在蒸散的持续性最强,天山山区次之,北疆地区最弱.

Fractural Character and Rescaled Range Analysis of Potential Evapotranspiration in Xinjiang Uyghur Autonomous Region

【Objective】 The purpose of this program is to forecast the potential variation tendency of the evaportranspiration in Xinjiang by analyzing the annual evaportranspiration time series and judging the fractural structure.【Method】The Penman─Monteith model was applied to calculate time series of potential evapotranspiration in 53 weather stations distributing in Xinjiang Uyghur Autonomous Region from 1955 to 2008,the fractural structure of the series was decided by partition function and the evaportranspiration time series was analyzed with rescaled range analysis on the tendency.【Result】There is a obvious linear relation between τ(q) and q in the partition function,and even when the q is equal to 10,20,…,100,the linear relation still remains remarkable.The Hurst exponents of South of Xinjiang,North of Xinjiang and Tianshan Mountains are 0.896 0,0.719 4,0.788 9,respectively,which means that there is a remarkable Hurst phenomenon in the three regions.【Conclusion】The evaportranspiration time series of South of Xinjiang,North of Xinjiang and Tianshan Mountains is a single fractural structure.The persistency of South of Xinjiang is the strongest,Tianshan Mountains is stronger and the North of Xinjiang is the weakest.