土地利用/覆被变化下流域泥沙输移的分形特征及尺度转换

Fractal Features and Scale Transformation of Watershed Sediment Transportation under LUCC

基于由WEPP模型提取的甘肃天水罗玉沟和吕二沟小流域单元侵蚀产沙及泥沙输移资料,采用分形维数理论,对流域泥沙输移比的空间分异规律、泥沙输移比的影响因子以及泥沙输移的尺度转换进行研究。结果表明:年均泥沙输移比有相当大的变幅,不同流域尺度上的泥沙输移比为0.03～1.00,对于一定尺度的流域,泥沙输移比是一个比较稳定的值;小流域泥沙输移过程具有分形特征;根据研究区流域泥沙输移比的分形特征,综合其他地区的研究结果,建立了小流域泥沙输移比尺度转换模型,同时建立了研究区适用尺度范围更广的流域泥沙输移比尺度转换模型。

Based on the information of soil erosion and sediment yield and transport extracted from watershed units of Luoyugou and Lv＇ergou by WEPP model,the spatial variation law and impact factors of sediment transport rate and scale transformation of sediment transport were studied using fractal theory.The results showed that the annual average sediment transport rate varied between 0.03 and 1.00 in various scales of watersheds,but it was stable for a given scale;the process of watershed sediment transport had fractal features,according to which a model of scale transformation for sediment transport rate was established integrating relative research results in other areas.Furthermore,an extensively applicable scale transformation model was given.