Exact solution of electromagnetic scattering by a three-dimensional hexagonal ice column obtained with the boundary-element method

The combined field integral equation is solved for electromagnetic scattering of a three-dimensional hexagonal ice column and is tested to investigate its applicability to radiation transfer in ice clouds. Convergence of a solution and the influence of rounding the hexagonal edges were checked, and no practical problems were found. The scattering characteristics of a hexagonal ice column are discussed from the size of the Rayleigh scattering region to the size at which a ray optics character appears. The size parameter of a hexagonal column is as much as 50, which was limited by computer resources.