Statistical Simulation of Spaceborne Lidar Pulse Propagation in Cirrus Clouds Taking into Account Multiple Scattering

Abstract

Laser remote sensing of cirrus clouds is accompanied by the problem of taking into account the multiple scattering of radiation, which influences the reliability of measurement interpretation. The contribution of multiple scattering of radiation to echo signals of a spaceborne lidar is estimated. The nonstationary problem of laser pulse propagation in continuous cirrus clouds with separation by scattering multiplicities is solved by the Monte Carlo method at different values of the optical and microstructural characteristics of clouds (optical thickness and shape and size of ice particles) and lidar parameters (distance from the sensing object, beam divergence, and field of view of the receiver). Numerical experiments were carried out taking into account the permissible range of the parameters for operational or promising spaceborne lidar systems. The features of the formation of the backward signal when aerosol and Rayleigh particles, as well as the underlying cloud layer, are introduced into the atmospheric model are discussed. The simulation results indicate the high sensitivity of the echo signal part caused by multiply scattered radiation to the parameters under study, which should be taken into account when formulating and solving inverse problems.