Calculations of the soil hot-spot effect using the coherent backscattering theory

The shadowing theory has been widely used to account for the hot-spot effect for the canopy and soil. However, it is not valid for soils that are composed of fine particles and do not have well-defined shadows. The coherent backscattering theory is used in this study to calculate both the magnitude and the angular width of the hot-spot peak for clay and silt soils. The soil hot-spot magnitude is calculated by solving the vector radiative transfer equation. The dense nature of the soil medium is taken into account in the calculations of the hot-spot angular width. The results are also linked with the Hapke hot-spot empirical function. The effects of the wavelength dependence and of particle size and shape also are exainined.