Study of color ratio for atmospheric ice particles to estimate their characteristic size from laser sensing data
D.N. Timofeev1,2, I.V. Tkachev1,2, A.V. Konoshonkin1,2, N.V. Kustova1,2, V.A. Shishko1,2
1V.E. Zuev Institute of Atmospheric Optics of Siberian Branch of the Russian Academy of Science, Tomsk, Russia
2National Research Tomsk State University, Tomsk, Russia
Keywords: atmospheric particle, lidar sounding, ice crystal, color ratio, physical optics, light scattering matrix, light backscattering
Abstract
The main problem in studying atmospheric ice particles is the lack of information on their morphology and size. Traditional active and passive monitoring methods do not applicable to determination of these parameters due to physical limitations of the wavelengths and spatial resolution. There is a need in alternative methods, such as near-infrared lidars, where the absorption effect of ice particles is sufficient. This effect causes differences in lidar signals, thus opening a possibility of retrieving particle sizes from the spectral ratio. In this paper, the color ratio of atmospheric ice particles with sizes from 5 to 1000 mm, typical of high-altitude clouds, is studied. The dependence of the color ratio on particle size is derived. The study uses the ScIce-2023 light scattering matrix database for random spatial orientation of particles and single scattering approximation. Several particle shapes typical for ice clouds are studied at incident wavelengths from 0.355 to 2.150 mm. The results can be used for interpreting data of ground-based and satellite laser sensing of crystal clouds.
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