APPLICATIONS OF A LASER SCANNER TO QUANTIFY SOIL MICROTOPOGRAPHY

Many transport processes on or across the soil surface boundary are controlled by surface microtopography, or roughness. How roughness affects the transport process depends on the length scale of the process. The most commonly used method of expressing soil surface roughness, the roughness length or random roughness, is constrained by the measurement technique and does not embody the concept of scale. The structural function, or variogram, plotted on a log-log scale was used in this study to express the surface roughness at different scales. With the aid of a laser scanner, surface topography was measured down to 0.5-mm grid spacing. Data collected from a variety of surface conditions showed that soil roughness can be quantified by a combination of fractal and Markov-Gaussian processes at different scales. Potential applications of the roughness quantification were also discussed.