Algorithm for Solving the Light Scattering Problem for Arbitrary Shaped Ice Particles with Absorption

Timofeev D.N,Borovoi A.G,Konoshonkin A.V,Kustova N.V

doi:10.1051/epjconf/202023708004

Abstract

The work presents the estimation of the absorption influence effect on the light scattering problem for atmospheric ice particles. The calculation of light scattering matrices was performed for two types of particles: the solid hexagonal columns and the arbitrary shaped particles. The range of the size for both types of particles varies from 10 μm to 1000 μm. The results of the research show an insignificant decrease of the value of the M11 element of the light scattering matrix for small-sized particles for all chosen wavelengths (0.355 μm, 0.532 μm, 1.064 μm и 1.6 μm), and a significant decrease for big-sized particles for a 1.6 μm wavelength.

Highlights

The light scattering problem of ice crystal particles in cirrus clouds is crucial for investigation of the solar energy transfer process
Maximal dimension of the particle (Dmax) on Ȥ in the backscattering direction for the solid hexagonal column and the arbitrary formed particle is presented in Figure 2 and the dependency of Dmax on ȥ is in Figire 3a and 3b
The analysis of results show that the absorption influence is insignificant for the ultraviolet and visible zone of the spectrum (0.355 ȝm and 0.532 ȝm wavelengths) for solving of the light scattering problem for ice crystal particles of cirrus clouds, because it’s value is less than basis points of percent regardless to the shape, orientation, and size of particle

Summary

INTRODUCTION

The light scattering problem of ice crystal particles in cirrus clouds is crucial for investigation of the solar energy transfer process. For solving the light scattering problem for ice particles it is difficult to apply exact numerical methods such as the finite difference time domain method (FTDT) [2, 3] or the discrete dipole approximation method (DDA) [4, 5] due to their high requirements for computational resources for big-sized particles [6] For this reason the problem is often solved with the geometrical and the physical optics approximation [7]. For taking the absorption into account the new version of the modified beam-splitting (MBS-1) algorithm [10] was developed It calculates light scattering matrices within geometrical and physical optics approximation for particles with flat facets. There is the feature that allows defining an arbitrary shaped particle in the new version of the algorithm

ESTIMATION OF ABSORPTION

CALCULATION

Findings

CONCLUSIONS