Extinction matrix of quasihorizontally oriented atmospheric ice crystals for visible and IR light
N.V. Kustova1, A.V. Konoshonkin1,2, D.N. Timofeev1, V.A. Shishko1
1V.E. Zuev Institute of Atmospheric Optics of Siberian Branch of the Russian Academy of Science, 1, Academician Zuev square, Tomsk, 634055, Russia
2National Research Tomsk State University, 36, Lenin Avenue, Tomsk, 634050, Russia
Keywords: коэффициент ослабления, матрица экстинкции, перистые облака, физическая оптика, рассеяние света, ледяные кристаллы, extinction coefficient, extinction matrix, cirrus clouds, physical optics, light scattering, ice crystals
Abstract
The paper presents an extinction matrix for an ensemble of ice hexagonal plates and columns. The extinction matrix for droxtals and bullets was estimated. The calculations were carried out for particles with characteristic sizes from 10 to 100 μm, for wavelengths from 0.3 to 10 μm, assuming a gamma distribution over particle size with the width parameter μ < 4. It is found out that for the visible light, the extinction matrix of an ensemble of atmospheric ice crystals is a unit matrix with a scale coefficient being equal to the doubled area of the particle projection. The error of such a representation does not exceed a tenths of a percent and does not depend on the type of crystals and their spatial orientation. It is also established that this representation of the extinction matrix is applicable in the IR region only to hexagonal columns, bullets, and similar crystals with the characteristic size larger than 20 μm when the wavelengths is less than 8 μm.
|
