Atmospheric propagation model for calculation of the aureole about a point source

Abstract

In the atmosphere, light scattering by molecules, particulates and aerosols causes an aureole around point-like sources. In various meteorological conditions, the radiance field coming from this aureole can be a non-negligible part of the total detected signal by large Field Of View sensors. In the framework of aureole's study, we have developed a method based on Monte Carlo calculation. The corresponding code permits to deal with monochromatic point sources in the 240 to 300 nm spectral range. The source's intensity angular dependency is axisymmetric and the atmosphere is described as a plane-parallel medium composed of a user defined constituents profiles. Systematic tests have been performed in order to evaluate the influence of the different input data on aureole results, such as ozone and 502 concentration values or ozone and aerosols concentration profiles. These computations will help us to define the set of meteorological parameters which need to be known accurately in order to compare computations with detected signals recorded during field experiments.