Inelastic scattering in planetary atmospheres. 2: Polarization of the rotational component

The inelastic part of Rayleigh scattering, which we previously showed can account for the partially filled line profiles of the blue sky observed at high spectral resolution, also explains the variation of polarization across a line profile. At lower spectral resolution, only the rotational part of the molecular scattering is needed to account for the polarization phenomena; translational (Brillouin) shifts can be neglected. Aerosol scattering, like the ground reflection, reduces the polarizations observed in the zenith sky by diluting the molecular (Rayleigh) component. Although the theory agrees well with existing data, more observations of high quality are needed for a thorough test of the Ring effect.