Scattering of Polarized Laser Light by Water Droplet, Mixed-Phase and Ice Crystal Clouds. Part I: Angular Scattering Patterns

Abstract

Abstract Laboratory studies of the angular scattering and depolarizing behavior of water, ice and mixed-phase clouds are described in Parts I and II of this report. In Part I, we present the theoretical background and experimental apparatus for determining the angular scattering pattern in the laboratory. The experimental results obtained with vertically and horizontally polarized laser light (0.6328 μm) are given in the form of normalized scattering phase functions to facilitate their comparison to theoretical predictions. Close agreement between Mie theory and experiment is found for water clouds when the measured cloud droplet size distribution is input into the computations. For ice crystal clouds containing small (<50 μm), randomly oriented particles, the agreement with theory using either the spherical or long cylinder shape approximation is less noteworthy due to the presence of more intense side-scattering and the absence of cloudbows in the experimental ice data. The scattering behavior of mixed-...