Condition for precise measurement of soil surface roughness

Simple equation to approximate the bidirectional reflectance from vegetative canopies and bare soil surfaces, " Appl. A reflectance model for the homogeneous plant canopy and its inversion, " Remote Sens. Geometric-optical bidirectional reflectance modeling of the discrete crown vegetation canopy: Effect of crown shape and mutual shadowing, " IEEE Trans. On the derivation of kernels for kernel-driven models of bidirectional reflectance, " " Directional reflectance distributions of a hardwood and pine forest canopy, " IEEE Trans.poral attributes of the bidirectional reflectance for three boreal forest canopies, " in Proc. Abstract—Whereas it is well known that electromagnetic scattering by a randomly rough surface is strongly influenced by the surface-height correlation function, it is not clear as to how long a surface-height profile is needed and at what interval it should be sampled to experimentally quantify the correlation function of a real surface. This paper presents the results of a Monte Carlo simulation conducted to answer these questions. It was determined that, in order to measure the rms height and the correlation length with a precision of 610%, the surface segment should be at least 40 l long and 200 l long, respectively, where l is the mean (or true) value of the surface correlation length. Shorter segment lengths can be used if multiple segments are measured and then the estimated values are averaged. The second part of the study focused on the relationship between sampling interval and measurement precision. It was found that, in order to estimate the surface roughness parameters with a precision of 65%, it is necessary that the surface be sampled at a spacing no longer than 0.2 of the correlation length.