The backward cross section of hexagonal ice crystals of arbitrary orientation is calculated for visible light by means of a ray-tracing code. It is shown that backscattering of the tilted crystals is caused by a corner-reflector-like effect. A very large peak of backscattering is found for a tilt of 32.5° between the principal particle axis and the incidence direction. This peak is caused by multiple total internal reflections for part of the rays that are incident upon the skewed rectangular faces. Slant lidar measurements for remote sensing of cirrus clouds are proposed.
© 2000 Optical Society of America
(010.1310) Atmospheric and oceanic optics : Atmospheric scattering
(010.2940) Atmospheric and oceanic optics : Ice crystal phenomena
(280.3640) Remote sensing and sensors : Lidar
(290.1350) Scattering : Backscattering
(290.5850) Scattering : Scattering, particles
Anatoli Borovoi, Igor Grishin, Edward Naats, and Ulrich Oppel, "Backscattering peak of hexagonal ice columns and plates," Opt. Lett. 25, 1388-1390 (2000)