Lattice Boltzmann Method for Electromagnetic Scattering by Complex Atmospheric Particles

We develop and assess a Lattice Boltzmann Method (LBM) framework for modelling electromagnetic wave scattering by atmospheric particles, with a focus on complex and aspherical geometries relevant to climate science and optical remote sensing. In this formulation, mesoscopic distribution functions for the electric and magnetic fields evolve on a discrete lattice, from which the macroscopic Maxwell equations emerge through a Chapman–Enskog expansion. The method inherently accommodates irregular boundaries, making it well-suited for non-spherical particle shapes. Scattering computations are performed for circular and hexagonal cylinders, as well as spherical scatterers. The results are benchmarked against analytical and semi-analytical solutions, such as classical Mie theory and the Discretised Mie Formalism. Across the Rayleigh, Mie, and geometric-optics regimes, the LBM accurately captures key scattering features, including edge diffraction, interference structures, and far-field distributions, while retaining second-order accuracy in space and time. With its entirely local update rules, strong parallel scalability, and flexibility in representing complex geometries, the LBM provides a promising framework for simulating light scattering by atmospheric particles such as ice crystals and aerosol aggregates. These results highlight its potential to complement existing scattering models and support improved optical parameterizations for weather, climate, and remote sensing applications.