土壤侵蚀模型研究中的几个问题

土壤侵蚀模型是定量研究土壤侵蚀的有效工具,探讨土壤侵蚀模型研究中的有关问题对于土壤侵蚀模型的发展及相关研究具有重要意义。从模型的过程模拟、模型时空尺度变异、模型验证和不确定性几方面对模型研究现状及局限进行了归纳和分析,认为:不同过程的模拟及其模拟方法的不同导致了各具特色的土壤侵蚀模型的出现;大多水蚀模型是对不同时空尺度上的水流及相应侵蚀过程进行模拟预测,在不同的时空尺度上,不同的侵蚀过程占主导地位;现实过程和现象的复杂性、观测方法和手段的限制以及模型的自身的局限性是导致土壤侵蚀模型预测的不确定性的主要原因;与GIS结合的强预测力、低数据要求的模型是土壤侵蚀模型发展的趋势。

Some important issues in the modeling of water erosion: A review

Soil erosion prediction technology has been proven to be a valuable tool for dealing with problems in the soil conservation and for advancing our understanding of soil erosion processes.Though substantial process has been made regarding the development and use of erosion models,still significant improvements are needed to describe many fundamental processes and their spatial and temporal variations.In this paper some weakness associated with present-day models for soil erosion by water are discussed,and some opinions on model development are proposed.It will be good for the next generation of erosion models.In the soil erosion models,which processes to be represented and how to represent them are two principles.Different processes represented and diverse methods used lead to the diversity of soil erosion models with different properties.The water erosion models tend to be complex and physically based,but they do not achieve high accuracy correspondingly because of the error accumulation and data availability.At different scales,different groups of processes are dominant,and the effective focus of the model also changes with scales.Itis important to keep represented and observed processes in the same spatio-temporal scale.The main reasons for the uncertainty of model performance are: complexity of natural processes and phenomena,difficulties in obtaining appropriate input parameter values,and built-in problems of the model.Models combined with GIS,which is characterized of high accuracy and low data requirement,are desired greatly.More attention should be paid to certain processes such as sidewall erosion,gravity erosion,and effect of crust and soil microbe,and methods to obtain data more accurately.Improved ways of dealing with heterogeneity and scale are needed.The multi-scale and regional scale model will also be the study foci.