Modelling of Electromagnetic Scattering at Infrared Wavelengths by Pristine Ice Crystals

Abstract

Cirrus clouds substantially impact Earth's atmospheric system, including its radiative budget, both of which enormously influence all scales of weather regions and processes. The shapes of ice crystals are ultimately determined by incident coordinate systems and relevant geometric models, specifically computational geometry and applied mathematics. and incident coordinate systems determine the shapes of ice crystals (Takano, Y. and Liou, K.N., 1995. Radiative transfer in cirrus clouds. Part III: Light scattering by irregular ice crystals. Journal of the Atmospheric Sciences, 52 (7), pp.818–837.). However, the scattering solution present in the infrared's spectrum area a complex dilemma. In previous attempts to solve scattering methods, such as Rayleigh theories, Mie and T-matrix methods, various established methods have been explored. However, it is important to note that such methods are faulty at infrared wavelengths because of size parameters, which can often exceed 100, consequently resulting in intensive computation. This paper presents a new approach based on physical optics and attempts to evaluate scattering by smooth prismatic dielectric ice crystals—specifically those which are electrically large. This method suggests that the total scattered amplitude in any trend can be measured by applying the reaction theorem to a volume interval from understanding internal field distribution. Subsequently, it is possible to convert this integral to an integral over an equivalent surface current distribution, thus, enabling total surface field analysis. The scattered field solution of the proposed physical optics method has been compared with ray-launching geometrical optics. Overall, the recommend method shows a good agreement when the scatterer is considered sizably large in comparison to wavelength. The proposed method exhibits good potential to be applied for ice crystals with rough surface structure.