Efficient calculation of orientationally averaged scattering from complex-geometry ice particles

A direct-solver based domain decomposition method is applied to efficiently compute orientationally averaged scattering efficiencies from complex-shaped ice pristine and aggregation. This numerically powerful method, known as the characteristic basis function method (CBFM), is based on the generation of a new set of basis function adapted to the geometry of the scatterer, in order to significantly reduce the numerical size of the EM problem. Being better adapted to multiple excitation problems, the CBFM enables us to achieve a significant reduction in CPU time in comparison to DDScat, a widely used implementation of the discrete dipole approximation (DDA), while maintaining a satisfactory level of accuracy.