Wavelength dependence of ice cloud backscatter properties for space-borne polarization lidar applications

We investigated the use of backscatter properties of atmospheric ice particles for space-borne lidar applications. We estimated the average backscattering coefficient (beta), backscatter color ratio (chi), and depolarization ratio (delta) for ice particles with a wide range of effective radii for five randomly oriented three-dimensional (3D) and three quasi-horizontally oriented two-dimensional (2D) types of ice particle using physical optics and geometrical integral equation methods. This is the first study to estimate the lidar backscattering properties of quasi-horizontally oriented non-pristine ice crystals. We found that the chi-delta relationship was useful for discriminating particle types using Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) data. The lidar ratio (S)-delta relationship, which is determined using space-borne high-spectral-resolution lidar products such as EarthCARE ATLID or future space-borne lidar missions, may also produce robust classification of ice particle types because it is complementary to the chi-delta relationship. (C) 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement