基于分形理论的坡面土壤侵蚀过程的情景模拟

Scene Simulation of Slope Soil Erosion Process based on Fractal Theory

针对现有的坡面侵蚀预报模型在提取地形地貌特征因子中的局限性,选取坡面在次降雨条件下随时间变化的过程,可视化的模拟了坡面的原始地貌。以计算机图形学的分形布朗运动为理论,采用随机中点位移法构造坡面地形,并在此基础上以黄土丘陵沟壑区坡面水分入渗和产流产沙的模型和试验结论为依据,提出了模拟坡面侵蚀过程的三层映射法:将土壤、降雨、植被的属性映射到坡面地形的三维空间,形成土壤层、水流层、植被层,通过图形处理的空闲回调渲染水沙运移路径随降雨过程及不同植被覆盖下的变化场景。结果表明,该方法能以分形维数真实的刻画坡面的地貌形态,以图形学和可视化技术验证侵蚀模型的正确性,在降雨-径流-产沙的研究中能够将科学计算与情景模拟有机的结合。

As the shortage of extracting the topographic feature of slope erosion prediction moadels,the changing process on slope with rain was selected, simulated the dimension of slope visually, which was guided by the method of random mid-point displacement based on Fractal Brownian Motion of computer graphics to construct the slope terrain, furthermore, based on the conclusions of experi- ments from infiltration and water-sediment in the Rolling Gullied Loess Region, a new mapping method of a three-layer for the simulation of the erosion process on slope, which mapped the attributes of soil, rain and vegetation to the 3D space of slope, generated soil layer, water layer and vegetation layer, rendered the moving route of water-sediment and the changing process under different vegetation coverage along with rain and erosion process in the call back function of idle image processing has been put forward. The results showed that the method can embody the authenticity of geomorphology of slope with fractal dimension, validate the correctness of erosion model with graphics and visualization technology, and combine with the scientific computing and scene simulation on the research of rainfall- runoff-sediment.