Physical-geometric Optics Hybrid Method for the Solution of Light Scattering by Nonspherical Particles

The ray/beam-tracing technique has been extensively used for solving the interaction between electromagnetic waves with particles whose characteristic dimensions are much larger than the incident wavelength. The accuracy of the derived solution improves as the particle size parameter increases. We present a thorough and update numerical treatment in the physical-geometric optics hybrid (PGOH) method of the solution of light scattering by nonspherical ice crystals and mineral dust aerosols in the atmosphere. The PGOH computes the optical properties by integrating the geometric-optics near field through the electromagnetic integral equations. When the particle is absorptive, the inhomogeneity of the waves within the particle is fully taken into consideration. The new PGOH is "exact" without making additional physical simplifications other than the geometric-optics principles. The accuracy of the PGOH solutions is examined in comparison with their counterparts derived from other numerical methods that solve Maxwell's equations. Furthermore, the accuracy and applicability of the PGOH method are comprehensively obtained.