Martian Blue Haze Clearings and Flash Phenomena

Abstract

THE relative lack of contrast in the blue (λ < 0.44 µm) in examinations of the surface markings of Mars has long been known, but occasionally and unpredictably, detailed blue structure can be seen briefly during blue haze clearings. There is some controversy about these phenomena^1,2, although in our opinion they are well established. A blue obscuring haze may be attributed to scattering of light by suspended particles^3–7 of diameter less than 0.4 µm, in the martian atmosphere so that blue haze clearings would result whenever meteorological conditions caused a partial precipitation of particles, but the mechanisms for the removal remain as obscure. We propose a simple meteorological mechanism which is consistent with available data from martian oppositions and flash observations.