The Inverse Theory: Twilight Sounding of the Mesosphere

Abstract

Up to this point we have endeavored to explain and calculate the principal twilight phenomena, and to clarify how the various properties of the atmosphere’s optical structure influence the course of these processes. The discussion has established that while secondary scattering of light by the atmosphere does contribute significantly during the bright portion of twilight — the semitwilight and total-twilight periods —it is not the predominant factor, and the distinctive features of twilight phenomena result from single scattering of direct sunlight that has been attenuated along the way to the scattering site. Secondary scattering is allotted a substantial role, but does not have a decisive impact.