Ice clouds and airborne dust are two important atmospheric constituents, as they substantially regulate the radiative energy budget in the earth-atmosphere system. The single-scattering properties of these atmospheric constituents are fundamental to achieving a better understanding of their roles from the radiation perspective, such as for applications to remote sensing technique implementations and radiative transfer simulations. Ice crystals and dust aerosol particles in the atmosphere are almost exclusively nonspherical particles with complex morphologies. In this paper, we report advanced modeling capabilities in computing the optical properties of these nonspherical dielectric particles in the atmosphere. In particular, we use an ensemble approach along with a combination of the invariant imbedding T-matrix method and the physical-geometric optics method to consider the effects of the overall nonspherical geometries and small-scale irregularities or surface roughness on the single-scattering properties of ice crystals and dust aerosols.