基于信息熵原理的东北地区参考作物蒸散量时空特征分析

根据1951—2013年东北地区116个气象站点的常规气象资料,基于信息熵理论构建了东北地区日参考作物蒸散量站点间的信息传输模型并分析了信息场的分布情况,利用聚类分析法解析了东北地区日参考作物蒸散量的区域相似性结构特征;并在此基础上选取6个代表性站点,运用重标极差法分析了参考作物蒸散量(ET_0)的时间分形特征。结果表明:空间上,东北地区日参考作物蒸散量的信息熵随纬度增加而减小,各站点信息传输指数随基站与辅站距离的增大而减小,且具有明显的各向异性;东北地区在站点群层面上的信息传输总体呈由南到北、由东到西的分布规律。时间上,东北地区多年平均ET_0总体呈下降趋势,哈尔滨、沈阳、赤峰、加格达奇、佳木斯、海拉尔6个代表性站点的ET_0在未来一定时段内的变化趋势趋于稳定且具有较强的持续性。

Analysis of temporal and spatial characteristics of reference evapotranspiration in Northeast China based on information entropy theory

Using conventional meteorological data from 116 meteorological stations in Northeast China from 1951 to 2013, an information transfer model of daily reference evapotranspiration(ET0)between stations in Northeast China was constructed based on the information entropy theory, and the distribution of the information field was analyzed. The regional similarity structural characteristics of daily ET0 were analyzed using the cluster analysis method. Then, six representative stations were chosen based on the analysis. The rescaled range analysis method was used to analyze the time fractal characteristic of ET0 at the six stations. The results show that, in space, the information entropy of daily ET0 decreases with the increase of latitude in Northeast China, and the information transfer index of each station, with significant anisotropy, decreases with the increase of distance between the basic station and the auxiliary station. The information transfer at the site level presents a general pattern of distribution from south to north and from east to west. In time, the mean annual ET0 presents a generally decreasing trend in Northeast China, and the ET0 of the six representative stations, i. e. , the Harbin, Shenyang, Chifeng, Jagdaqi, Kiamusze, and Hailar stations, will tend to stabilize within a certain time period in the future and show strong persistence.