Lidar signal model from remote aerosol formations in double scattering approach

Lidars are applied in many geophysics, meteorology and atmospheric optics research. However, the problem of lidar data interpretation is not solved yet. It is necessary to take into consideration the multiple scattering (MS) when laser radiation propagates in optically dense aerosol formations. The paper discusses the problem of numerical simulations of the lidar returns that account for contributions from single and double scattering from dense aerosol formations. We have analyzed the lidar equation that was obtained in Samokhvalov (1979) for an inhomogeneous atmosphere with account of single and double scattering. It is shown in the paper that double scattering "forward-backward" and "backward-backward" photon trajectories equally contribute to the backscattering intensity. This significantly simplifies the lidar equation, if the sounding pulse penetrates the cloud to the depth that is small compared with the diameter scattering volume at the cloud top.