Abstract: SWAT model is a distributed hydrological model, which was based on GIS. It got frequent development and application in recent years. SWAT model was developed to simulate varying hydro-physical processes including water, sediment and agricultural chemical yields in large complex watersheds. The water balance of the SWAT model was expatiated and it was applied to simulate the rainfall-runoff relationship in the Suomo Basin in order to reveal the impact of climate fluctuation and land-cover changes on hydrology. The result was that, from the 1960s to the 1990s, 1/5-runoff change was caused by land-cover change and 3/5～4/5-runoff change was caused by climate fluctuation.

Key words: SWAT model, distributed hydrological model, water balance, the Suomo Basin

摘要： SWAT模型是一种基于GIS基础之上的分布式流域水文模型，近年来得到了快速的发展和应用。SWAT模型能够利用遥感和地理信息系统提供的空间信息模拟多种不同的水文物理化学过程，如水量、水质、以及杀虫剂的输移与转化过程。主要介绍SWAT模型水量平衡模块的原理和结构，并在梭磨河流域应用，旨在揭示梭磨河流域的气候波动和土地覆被变化对流域径流的影响。结果表明，20世纪60—90年代，梭磨河流域的径流变化中，由气候波动引起的约占3/5～4/5，由土地覆被变化引起的约占1/5。

关键词: SWAT模型, 分布式水文型, 水量平衡, 梭磨河流域