水文干旱的时间分形特征探讨

介绍了分形理论的基本概念及其分维计算方法．探讨了干旱要素在一定标度范围内的统计时间分形特征．通过实例分析表明：不同程度的干旱现象具有各自的时间演变规律，时间分形与干旱发生的周期存在反相关关系，即时间分维越小，干旱发生的周期越长，干旱现象越严重；而轻轻的干旱现象则以短周期为主，发生频繁，分维值较高．时间分维有可能对干旱规律的认识和预防有重要价值．

Investigation on the Time Fractal of Hydrologic Drought

In this paper, the fractal study is applied in the analysis of hydrologic drought,and some characteristics of drought about time fractal features are investigated. The analysisshows that different seventy of drought has different time span. The time fractal is inversely proportional to the drought cycle. The smaller fractal dimension is, the longer drought span is andthe more heavy drought damage is. Conversely, the lighter drought with bigger fractal dimensionfrquently happens, and has a shorter time span. Therefore , the fractal dimension may be veryhelpful to understand and forcast the hydrologic drought.