Lidar effective multiple-scattering coefficients in cirrus clouds

摘要

We delimit a regime, valid for most ground-based lidar probings of cirrus clouds, in which the field-of-view dependence of multiple scattering reaches a plateau. In this regime and assuming the phase function to be constant around π, we formally demonstrate Platt's modification of the single-scattering lidar equation, with a parameter ηρ accounting for the reduction of the effective scattering coefficient defined so that (1 -ηρ) is the amount of energy scattered in the forward peak. Then, to cope with nonconstant backscattering functions, we discuss the introduction of an effective backscattering coefficient that is an average of the scattering probabilities aroundπ.# 1997 Optical Society of America