珠江三角洲典型站水位过程变异性的差异熵识别

Recognition on Change of Stage Processes at Typical Gauge of the Pearl River Delta Using Difference Entropy Theory

采用差异信息熵理论 ,建立了水位过程变异性识别的差异信息熵方法。以近 10年来水文特征变异显著的珠江三角洲网河区南华、紫洞站近 4 0年逐月长系列水位资料为典型 ,进行水位变异性差异信息熵识别 ,结果表明 ,南华和紫洞站水位过程具有相似的变异特征 ,南华站在 196 6、 1980及 1992年发生了异变 ,紫洞站在196 7、 1980及 1992年发生了异变。水位异变与珠江三角洲几次大规模人类活动十分一致。

In the river network of the Pearl River Delta, man_induced change of hydrological processes is so great that the previous schemes for hydrological forecasting, flood control and water use are inapplicable. To identify the time of change of the hydrological processes in the past several decades in the Pearl River Delta, a recognition method with difference entropy is developed based on the entropy theory. Using the specific gauge records of monthly stage in recent forty years in the river network of the Pearl River Delta, the split spots of time for the change of stage processes at two specific gauge stations, Nanhua and Zidong, are identified according to the diffraction on the cumulative curve of the difference entropy of stage process. The results show that water level process at Nanhua Station have happened bias changes in 1966, 1980 and 1992 respectively since 1960,while the bias changes of stage process at Zidong Station occurred in 1967, 1980 and 1992 respectively since 1958. The three bias changes spots cut the stage process into 3 periods with different streamflow characteristics which are in accordance with the dramatic human activities in the Pearl River Delta:① Dykes combination and sluices construction before the 70s cause the rise of water level and the first bias change of stage process in about 1967; ②Dynamic adjustment of river sections due to the concentration of flow during the first period results in the recovery of the rising stage and the second bias change of stage process in about 1980; and ③Large amount of sand dredge in the river, intensive reclamation and dense construction of bridges and docks along the river starting the early 80s give rise to the third bias change of stage process in about 1992.