Use of double scattering in lidar applications

The lidar approximation for a monostatic sounding system is obtained in a double-scattering approximation. The result is an integral Volterra equation of the first kind with a difference kernel. A numerical analysis is made of the limits of validity of the double-scattering approximation. The Monte Carlo method is used in calculations for two types of media. Quantitative estimates of the functional nature of the kernels are obtained for three types of fog and three cloud models.