In the northern hemisphere at high latitudes (60 degrees), the level of "large" fraction of aerosol extends to an altitude of 30 km, the average - rises to 40-50 km, with over 20 km is mostly water ice, and below - dust. Particle radius is about 0, 76 microns (dust) and 1, 2 microns (water ice), and the concentration ranges, respectively, in the range 0, 4-2 and 0, 01-0, 3 particles per cubic cm.
"Small" dust much more: At 10 km the number comes to 10,000 particles per cubic centimeter, and only 30-35 km - 100 particles in the same volume. Its average size coarsens from the pole to the equator: 0, 039 mm at latitudes above 60 degrees and 0, 048 - lower (mean value 0 and 044 microns).
In the southern hemisphere, as is known from other observations, the atmosphere is generally quite clean. The average size of the large particles of dust at latitudes above 50 degrees was 0, 75 m, and the number per cubic centimeter varies from 0, 1 and 2. The water ice particles are larger - radius approximately equal to 0, 86 m, the concentration is changed from 0, 005 0 to 05 per cubic cm. The average radius of the fine dust is greater than the north: 0, 07 micrometers - and the concentration decreases with height from 100 (35 km) to 0, 6 particles (70 miles) per cubic cm. low latitudes, the sky is almost clean, and the aerosol concentration is low.
Interestingly, however, that in this area at altitudes of 40-50 km in the ultraviolet range showed a layer of mist until a certain composition. If this dust, particles having very small (0, 06 microns), and their number per cubic centimeter very large - from 100 to 3000. In the case of water ice particles size becomes slightly larger, and the concentration, by contrast, is less. Its existence, this layer may be required to global flows of warm air masses from the northern (summer) hemisphere to the southern, where they cool and sink (called Hadley cell). This circulation is typical for the season, a close solstice in both hemispheres.
From the press release of Sciences i> blockquote> The concentration of particles in the Martian atmosphere is not high. By earthly standards, it is pure atmosphere. Even in the "dusty" areas of Mars concentration of particles smaller than usual in the air of the room until the dust storm begins.
Interestingly, the role played by aerosols in the climate system of Mars. The fact that the above described composition of the particles in the atmosphere can not exist for a long time. Obviously, it is replenished from outside. A source of new particles can be dust from the surface of the planet.
The modern climate of Mars is interesting in itself, because it is unique among the terrestrial planet with a condensing atmosphere and climate system is largely controlled by the spray. In addition, the planet may have experienced catastrophic climate change and save the following past climates, suggest scientists from MIPT.
Source: habrahabr.ru/post/227471/