Refraction, specifically the real component of refraction n (describes bending of
rays, wavelength
changes relative to a vacuum, affects blackbody fluxes and intensities — as opposed to the imaginary component, which is related to absorption and
emission) is relatively unimportant to shaping radiant fluxes through the atmosphere on Earth (except on the small scale processes where it (along with difraction, reflection) gives rise to scattering, particularly of solar radiation — in that case, the effect on the larger scale can be described by scattering properties, the emergent behavior).