分形是研究土壤表面不平度的有效方法,选择合适的分形维数计算方法是准确表征表面轮廓的关键.利用w-M理论分形曲线对常用于计算表面轮廓分形维数的4种方法进行评价,结果显示均方根法在表征分形维数介于1.2-1.6的表面轮廓时精度最高;均方根法在表征实测土壤表面时的适应性强,无标度区间宽.根据表面轮廓的均方差与区间尺度呈比例的性质改进了均方根法,理论轮廓曲线的计算结果显示其精度明显提高,为准确描述土壤表面的复杂特性提供了一种有效的方法.%Fractal characterization is an effective way to investigate the soil surface roughness. An appropriate fractal dimension computation method is critical to obtain the accurate results. Four methods commonly used for computing the fractal dimensions were evaluated by using the W - M fractal profile curves. The results showed that the mean-root-square method had the highest accuracy in describing the soil surface roughness with fractal dimension between 1. 2 and 1.6, it had a good adaptability in characterizing the real measured soil surface roughness. Based on the fact that the mean-root-square difference of surface roughness was proportional to the section scale, the mean-root-square method was improved. Compared with the theoretical curves, the new method showed a higher accuracy and provided a new method for describing the complex characteristics of soil roughness.
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