The global climate change and intensification of human activities in recent decades have made profound changes in hydrological cycle processes and water resources,and produced serious water problems and water crisis in many areas.The main reason is that the driving force of water cycle,the structure of water cycle,and the parameters of water cycle have dualistically evolved under the influence of human activities,and consequently resulted in reduction of runoff water resources,water pollution,and degradation of natural ecosystems.In order to realize of the safety aim of water supply,water environment,and ecosystem in area which is short of water resources,scientific regulation of water resources must take basin water cycle system as the unified base,and the first scientific basis is the awareness of the internal mechanism and law of water cycle evolution under highly intensive human activities.This article discussed four aspects of dualistic water cycle evolution,including its history in China,its theory,its characteristics in a typical basin,and its description of integral structure,along with the conceptive model system to quantify it.This article can be a reference to the basic cognition of water cycle evolution in a changing environment,and the study of water resources reduction reasons in the contemporary age.
为了描述城市区域水文过程,该文利用中国水利水电科学研究院水资源研究所开发的分布式水文模型Simulating Model for Urban Water Cycle(URMOD),以北京市四环路以内区域为例对不同下垫面蒸散发量进行了模拟计算。结果表明,城市区透水区域和不透水区域的蒸散发规律有很大差别,模拟期2002-2005年,草地、林地和水面的年均蒸散发量分别为578.4、571.2和1130.5mm,而不透水区域的年均蒸散发为161.0～269.1mm。将模拟蒸散发量和遥感反演数据进行对比,模拟月蒸散发数据系列与遥感反演结果吻合度很好。该模型可以有效模拟城市区实际蒸散发量。
