Title: Preliminary results of astrophysical observations of Mars from Mars-3
Abstract: On board the Automatic Interplanetary Stations (AIS) Mars-2 and -3 four experiments intended for studying the surface and the lower atmosphere of the planet with optical techniques were intalled: an infrared radiometer, a narrow-band photometer for CO2 spectroaltimetry, a narrow-band photometer for measurements of the H2O content of the atmosphere, and a photometer for measurements of the brightness distribution over the planet in several narrow spectral intervals between 3700 and 7000 Å. Preliminary results of measurements with these experiments on Mars-3 in seven periares passages between December and March are presented. The dark areas are warmer, systematically, by 10–15° than the bright areas; in some cases (the region Cerberus) in order to account for this elevated temperature one needs to postulate an increased thermal inertia in the dark areas. The temperature in the region of the northern polar hood is lower than 160°K. During the dust storm the surface was colder than after its termination. It seems that the temporary cloud layer arising during the dust storm creates a kind of “anti-greenhouse” effect. The heights measured by CO2 altimetry are in satisfactory agreement with the results of earth-based radar measurements, where this comparison is possible. The height of clouds during the storm was about 10 km, but the upper boundary seems to be dispersed. The water vapour content of the Martian atmosphere was very small, of the order of several microns of precipitable water in a vertical column from December to February; in March it increased, apparently up to 20μm. In the equatorial regions the humidity is somewhat higher than in the northern circumpolar region; the content of H2O over the northern circumpolar region is less than 0.5 μm. The comparison of photometric profiles of Mars in the region of 0.7 and 1.4 μm shows a considerable increase of contrast towards long wavelengths during the storm. This corresponds to particles of about 1 μ in size. During the dust storm the observed bright ultraviolet clouds are associated, apparently, with even smaller particles.
Publication Year: 1972
Publication Date: 1972-10-01
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 33
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