title: Martian dust storm: its depth on 25 november 1971.
abstract: Carbon dioxide absorption on Mars was observed by Earth-based spectroscopy at 10,500 angstroms. Its abundance was equivalent to a partial pressure of 2.0 millibars instead of the normal 5.5 millibars. The dust layer was therefore opaque to a height of about 11 kilometers. On 10 December, a pressure of 5.8 millibars was found.
authors.forename: T D
authors.initials: TD
authors.lastname: Parkinson
authors.forename: D M
authors.initials: DM
authors.lastname: Hunten