Ice clouds over the Martian volcanos from KRFM experiment data (mission Phobos).
Abstract
The results of the analysis of spectrophotometric observations of Mars carried out during February - March 1989 from the spacecraft "Phobos-2" obtained above the mountains Pavonis Mons and Arsia Mons are presented. The measurements were made in 7 narrow spectral bands from 315 to 550 nm. The brightness increase in short wavelengths over these regions may be explained by the presence of condensation clouds consisting of water ice particles. Using the model calculations by Mie theory for spherical particles, the sizes of icy particles are evaluated and the influence of an irregular shape of particles and the possible presence of a silicate nucleus in them on the properties of clouds is estimated. At least there are two possibilities (they may be realized simultaneously): 1) the clouds consist of small particles with an effective radius 0.5 μm, their optical depth is ≡0.2, 2) the particles consisting clouds are a bit larger (effective radius is about 1.0 μm), the optical depth of such clouds is 0.07 - 0.1. The clouds of small icy particles are over the volcanoes; and (or) the clouds consisting of larger particles are below the peaks at the altitudes about 15 km. The column mass density is evaluated in the limits 3.5×10-6 to 5.0×10-6g cm-2 in dependence on the assumed sizes and shape of cloud particles.
- Publication:
-
Astronomicheskii Vestnik
- Pub Date:
- February 1993
- Bibcode:
- 1993AVest..27...19P
- Keywords:
-
- Atmospheric Models;
- Ice Clouds;
- Mars (Planet);
- Spectral Reflectance;
- Volcanoes;
- Ice Nuclei;
- Mie Scattering;
- Optical Thickness;
- Particle Mass;
- Particle Size Distribution;
- Spectrophotometry;
- Lunar and Planetary Exploration