用仿真方法模拟研究黄土高原的变迁

RESEARCH ON THE VICISSITUDES OF THE LOESS PLATEAU BY THE SYSTEMATIC ANALOGUE SIMULATION METHOD

本文介绍了采用系统动力学方法模拟研究黄土高原变迁的结果。文中概略地介绍了系统动力学方法、仿真模型的建模过程、模型应用研究等具体内容,为便于阅读和研究,文中还附有系统动力学模型流图、模型参数代号及说明。

The loess has 2.4Ma history, and its formation and development are a very complex and slow natural course. The piling-up course of the loess is mainly related to the atmospheric ctivities of various scales, and its erosion is mainly affected by the precipitation and the wind. The human activities also influence the environmental vicisstude of the loess region. The future development of the loess plateau will be seriously affected by the human activities in addition to the slow natural action. In the modern time with rapid changing science and technology and economy development, the effects of human activities on the environment vicissitudes of the loess region will be increasingly obvious. When environmental changes of the region are studied, human actions and effects should be given attention besides the natural action and law in order that human activities of reforming natural environment aiming to improve and develop the social and economy consideration will be conducive to the subsistence and development of humankind. With all the above in mind, we adopted the method of Systems Dynamics and made systematic analogue simulation research on the environment vicissitude and development of the loess region. The Systems Dynamics is the methodotogy for studying the movement law of the complicared feedback system, namely the experiment method of simulating and studying the real system movement law on the computer using the established mathematics model. The method has the characteristics of dynamic, integration and feedback. The whole research model includes three parts——system identification, model building and practical application. The present work has established model Ⅰ and model Ⅱ. Model Ⅰ is to simulate the vicissitude law of formation and development of the loess, and model Ⅱ is to simulate the future development trend of the loess plateau under human and natural actions. We adopted different countermeasure plans to conduct pratical research of simulation so as to provide the technical data for the decision on harnessing the loess plateau. The work presents the main reason result relation map of Model Ⅰ and Ⅱ, the flow map of designing, computer progamme and the result of model simulation. The simulation results of model Ⅰ suggest that 2.5Ma ago the region was not covered by the loess, and the ravine area of the ground was small, and the Earth's surface was covered by the grasslands and forest; 0.01Ma ago the region was covered by the loess, and the ravine was developed to some extent which aggravated the water and soil loess of the region. The model Ⅱ firstly simulated the 250 year-development trend based on the present natural growth rate of the population.