The objective of this research is the assessment of electromagnetic scattering from spherical aerosol particles possessing internal inhomogeneities. A theoretical study entailing an exact solution of the electromagnetic boundary value problem, along with an investigation of various approximation schemes, will be conducted. In order to corroborate the theory, laboratory tests of the model will also be made. An aerosol model based on a survey of the physical and atmospheric chemistry associated with the formation of sulfate and carbonaceous aerosols and their composites will be developed. The optical properties of composite particles provided by that model will be used in a sensitivity study of the radiative properties of the aerosol and of the droplets for which the aerosol particles serve as condensation nuclei. As a final exercise, a model albedo of cirrus clouds that are made up of particles possessing internal structure will be contrasted with cirrus models that employ spheres, sphere aggregates, and small crystals as cloud particles.
