Application of a scanning polarization lidar for the investigation of the particle orientation in cirrus clouds

摘要

Scanning polarization lidar LOSA-M3 is designed to study of the optical characteristics of crystal clouds of the upper and middle layers at two wavelengths - 532 and 1064 nm. Lidar allows you to smoothly change the angle of inclination from the vertical with simultaneous conical (azimuthal) scanning. Such a measurement scheme makes it possible to study in detail the preferential orientation of ice crystals in the clouds. The lidar simultaneously measures the polarization characteristics of signals for linear and circular initial polarizations, which allows to obtain additional information about the anisotropy of scattering particles, including exploring the azimuthal orientation of the particles. The first results of observations of the crystalline cloud polarization structure carried out in Tomsk in April-October 2018 are presented in the article. The results show that the contribution of horizontally oriented particles giving a specular reflection can vary significantly in different parts of the cloud.