The Effect of the Shape of Dust Aerosol Particles in the Martian Atmosphere on the Particle Parameters

The influence of the shape of dust aerosol particles in the Martian atmosphere on the imaginary part of the refractive index ni as derived from photometric observations during the period of the highest activity of the dust storm in 1971 was studied and exemplified for particles of spherical and oblate spheroidal shape. A similar analysis was performed for mean particle radii r0 and optical thicknesses τ0 of the dust layer estimated from polarization observations for periods of high atmospheric transparency. It was demonstrated that the values obtained for these optical parameters are affected by the adopted aerosol shape. Namely, the values of ni, r0, and τ0 found for spheroidal particles proved to be nearly twice as large as those for spheres. However, they are still much less than the available estimates of these parameters inferred, in particular, from interpreting space experiments. The reason for this difference needs further investigation.