Mars: Mariner 9 Spectroscopic Evidence for H ₂ O Ice Clouds

Abstract

Spectral features observed with the Mariner 9 interferometer spectrometer are identified as those of H(2)O ice. The measured spectra are compared with theoretical calculations for the transfer of radiation through clouds of ice particles with variations in size distribution and integrated cloud mass. Comparisons with an observed spectrum from the Tharsis Ridge region indicate H(2)O ice clouds composed of particles with a mean radius of 2.0 micrometers and an integrated cloud mass of 5 x 10(-5) grain per square centimeter.