Martian Clouds Research Articles

Television observations of Martian cloud formations in 1973: Preliminary results

During the period July 14–September 11, 1973, about 25 000 television pictures of Mars were obtained using a 0.7m telescope in ten spectral regions. A dust storm in moderate latitudes was recorded. It started before Mars passed perigee. During the observation period the atmosphere was gradually clearing. About 3000 pictures of Mars were taken using a 0.5m meniscus telescope during the period of Nobember 19, 1973–February 19, 1974. On November 19 the atmosphere was very hazy and heavy dust clouds were recorded. The second dust storm cleared during December through January.

Ground-based television patrol of Martian cloud formations in 1969 and 1971–1972

Particular advantages of T.V. techniques for planetary observations are: high quantum efficiency, possibilities for registration of features with low contrasts, and convenient control of seeing. The photometric accuracy of T.V. pictures was found to be about 6–8%. When Mars was surveyed by Mariner 6 and 7 our groundbased T.V. photos showed the existence of bright cloud formations over northern polar regions and over the Hellas-Ausonia regions. About 50 000 T.V. pictures have been obtained in ten spectral regions (370–760 nm) during the period of August 1971 to January 1972. Television observations showed that the date of initiation of the global dust storm was September 12 when two red clouds appeared in the Hellespontus and Moab regions. For a period from about the middle of October to November 25 all surface features were obscured by a heavy dust storm. The general decline of the Martian dust storm was followed by the appearance of local dust clouds.

Mars: Are Observed White Clouds composed of H2O?

MARTIAN clouds have been classified1 into Type I, which are visible at short optical wavelengths, and become gradually invisible as the wavelength increases; and Type II, which are visible at long wavelengths, and fade into invisibility when the wavelength decreases. The three principal kinds of observed Martian clouds—yellow, white, and blue—can be categorized as Type I, blue; and Type II, yellow and white. This distinction is essential. Yellow and white clouds are classified together because they are visible in the same wavelength range; yellow clouds are dust clouds and will not be described here.

…also of Interest: Space and Cryogenics

Union Carbide has made a micrometeroid detector so delicate that it will record velocity and direction without changing either. Aluminum films on both sides of a plastic sheet produce signals that tell where and when a particle ruptured each of them… If you want to see a satellite better, illuminate it with a laser and make a hologram with the reflection. You should beat atmospheric distortion say Stanford engineers Joseph Goodman, Wright Huntley, David Jackson and Matt Lehmann… Mohave Desert dust devils, those frequent summer cyclonic systems, may be a clue to yellow clouds on Mars say Jack Ryan and Ferol Fish of Douglas Aircraft, who are watching them to find out whether Martian clouds might have 350-mile/hr velocities and be dangerous to man.

Some Comments on Martian White Clouds

Some Comments on Martian White Clouds

Possible condensation clouds over Martian volcanoes.

An unusual Martian cloud, observed in 1954 by Pettit and Richardson (1955), had the form of a letter "W," with dense knots at ends and junctions of the strokes. The strongest knot was at longitude 120?6, latitude - Io?8. They called attention to an apparent association of the knots with oases. Some of the cloud knots, including the strongest one, were found near the same locations at two times a month apart. Slipher's observations (Sinton 1955) showed that they disappeared at night and re-formed each afternoon. I am much indebted to 0. H. Truman of Hollywood, Calif., for making available photographs he took in 1941 with the ioo-inch telescope. One in blue light, August 18, 11h48m UT, shows a cloud 100 in diameter near the terminator, with center at longitude I 15?8, latitude - I7?o, near Phoenicis Lacus. A tail extends to longitude 1030.5, latitude - 6?2, near Tithonius Lacus. Clouds in the same small area were photographed in 1939 by Wright (1939) and in 1926 by Ross (1926) and Wright (1927). The center of the cloud of 1926, October 14-18 was at longitude I20?8, latitude - I2?6. Thus, on four occasions over an interval of 28 years, unusual clouds have appeared in the same small area. On the last occasion they formed repeatedly about the same place. A mechanism associated with a fixed location on the planet's surface is indicated. Condensation of moisture from air currents rising along a mountain front is improbable, in view of the lack of mountain ranges on Mars. Condensation of moisture issuing from volcanic vents is suggested as a working hypothesis. The region of cloud formation is also one in which great changes have occurred on the surface. The "horn" of Phasis in 1877 had its vertex at Phoenicis Lacus. In 1926 the Solis Lacus was distorted by a new marking that appeared to fan out from a spot in Tithonius Lacus. These can be explained as ash falls from eruptions at those spots (McLaughlin 1955). The coincidence of an area of recurrent cloud formation with one of strong surface change is too close to be dismissed as accidental. Volcanism is an adequate explanation of both the superficial and atmospheric phenomena, and of their association. McLaughlin, D. B. 1955, A. J. 6o, 263-264. Pettit, E. and Richardson, R. S. 1955, Pub. A. S. P. 67, 65. Ross, F. E. 1926, Ap. J. 64, 243. Sinton, W. M. 1955, Sky and Telescope 14, 362. Wright, W. H. 1927, Lick Obs. Bull. 13, 50. 1939, Pub. A. S. P. 5', 292. University of Michigan Observatory, A nn Arbor, Mich.

The project on planetary atmospheres at the Lowell Observatory.

view Abstract Citations References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The project on planetary atmospheres at the Lowell Observatory. Hess, Seymour L. Abstract The project on planetary atmospheres represents a cooperative attempt on the part of both astronomers and meteorologists to pool their respective techniques and specialized knowledge in order to further our understanding of the atmospheres of the planets. The work of the project may be illustrated by a study of the horizontal temperature distribution on Mars based on the radiometric observations of Coblentz and Lampland. From this temperature field combined with 18 observed Martian cloud drift directions, it proved possible to draw a map of the normal horizontal wind distribution during Martian southern hemisphere summer. The main conclusion drawn was that these distributions are quite similar to those found on earth, being characterized by warm, subtropical, high pressure circulations and middle latitude westerlies. Sharp shears in the winds were found that are very suggestive of the shears found around fronts on terrestrial weather maps. The similarities found are not surprising in view of the resemblance between the two planets in such important meteorological parameters as length of day and inclination of the rotation axis. An anomalous patch of high temperature, associated with a cyclonic circulation resembling the terrestrial "heat low," was discovered and found to be located over a dark surface marking which appears seasonally in the Deucalion region. Lowell Observatory, Flagstaff, A ris.. Publication: The Astronomical Journal Pub Date: October 1950 DOI: 10.1086/106439 Bibcode: 1950AJ.....55R..73H full text sources ADS |