Parameterization of tillage-induced single-scale soil roughness from 4-m profiles

Soil roughness greatly affects the scattering process of microwaves to the soil surface. Previous studies showed that the values of roughness parameters increase asymptotically with increasing profile length. In this paper, 25-m profiles are used to study the influence of profile length on the roughness parameters and on the shape of the autocorrelation function. It is further investigated whether correct soil roughness parameters, as obtained from long surface roughness profiles, can be determined from 4-m-long profiles. Therefore, the extrapolation of an empirical relationship between roughness parameters and profile length is investigated, for three different roughness classes. The technique yields parameter values which are comparable to the 25-m roughness parameters.