杜仲人工林蒸腾时间演变的分形特征及可预报时长  

Predictability Time Scale and Fractal Characteristics of Temporal Variation of Eucommia ulmoides Plantation Transpiration

作　　者：张劲松[1] 孟平[1] 高峻[1] 王鹤松[1] 任庆福[1] 贾长荣 

机构地区：[1]中国林业科学研究院林业研究所,国家林业局林木培育重点实验室,北京100091 [2]济源市大沟河林场,河南济源454650

出　　处：《林业科学研究》2009年第6期807-812,共6页Forest Research

基　　金：国家自然科学基金资助项目(30471371);科技部公益性项目(2003DIB4J142);国家“十一五”攻关课题(2006BAD03A11)部分研究内容

摘　　要：以华北山地杜仲人工林为例,利用热扩散液流法测算得到的蒸腾数据,采用相空间重建法,在延滞时间(τ)为30 min条件下,分析林木蒸腾时间演变的分形特征及可预报时长,结果表明:林木蒸腾的时间演变过程具有分形和混沌特性,存在可预报性。2005年及2006年主要生长季节期间(4-9月),蒸腾时间序列的分形维数(D)分别是1.673和1.525,二阶Renyi熵(K2)分别为0.00249和0.00253,此时嵌入维数(m)分别为9和10,平均可预报时长(T)分别约为401.0、394.8 min。尽管2005年和2006主要生长季节蒸腾的外表变化规律或数量等存在较大的差异,但在相同τ条件下,D和K2在该2年间差异均很小,说明蒸腾时间序列的内在变化特征在不同年份间无差异。A case study with Eucommia ulmoides plantation in the mountainous region of North-China, predictability and fractal characteristics of temporal variation of trees transpiration were analyzed by using the method of reconstructing phase space when the lag time is 30 minutes. Transpiration measured with the technique of thermal dissipation probes in 2005 and 2006, The results showed that temporal variation of the plantation transpiration is a chaotic motion and characterized with fractal pattern and predictability during the main growth season. The fractal dimension （D）, Renyi entropy （K2）, embedding dimensions and the average predictability time scale of time series for the trees transpiration were 1. 673, 0.002 49, 9 and 401.0 minutes in 2005, respectively, and 1. 525, 0.002 53, 10 and 394.8 minutes in 2006. There existed significant difference in external appearance of temporal variation or in the amount of transpiration between the two years, but no difference about D and K2at the same lag time. It is concluded that there were no differences in natural characteristics or internal patterns of time series in different years.

关 键 词：杜仲人工林 蒸腾 相空间重建 分形 可预报性 

分 类 号：S161[农业科学—农业气象学]