A post-pioneer Venus reassessment of the Martian dayside ionosphere as observed by radio occultation methods

Conference · Thu Aug 30 00:00:00 EDT 1990 · Journal of Geophysical Research; (United States)

OSTI ID:5445162

Zhang, M H.G. ^[1]; Luhmann, J G ^[2]; Kliore, A J ^[3]; Kim, J ^[4]

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1. Univ. of Graz (Austria)
2. Univ. of California, Los Angeles (USA)
3. Jet Propulsion Laboratory, Pasadena, CA (USA)
4. Univ. of Michigan, Ann Arbor (USA)

The dayside altitude profiles of the electron density obtained with the radio occultation experiments on Mariners 4, 6, 7, and 9 and the Viking 1 and 2 spacecraft are collectively reanalyzed to determine the global characteristics of the dayside ionosphere of Mars. These analyses concentrate on the comparison of the properties of both the electron density peaks and the topside profiles with the behavior expected for a Chapman layer and that observed at Venus with the Pioneer Venus orbiter radio occultation experiment. As at Venus, the peak densities at Mars behave much like Chapman layer peaks with only slight departure from a (cos{theta}){sup 1/2} dependence, where {theta} is the solar zenith angle. In contrast, the peak heights depart from ideal Chapman layer behavior at Venus but not at Mars because the dayside neutral atmosphere at Venus depends on solar zenith angle. The global dust storm during the Mariner 9 main mission appears to have elevated the Martian ionosphere as a whole by {approximately}20-30 km without otherwise notably altering its density profile. These results generally corroborate the findings of earlier studies. An examination of the solar zenith angle dependence of density levels on the topsides of profiles obtained both at Mars and at Venus near solar minimum provides a new perspective on the solar zenith angle variation of the scale heights of the two ionospheres.

• OSTI ID: 5445162
• Report Number(s): CONF-9001119--
• Journal Information: Journal of Geophysical Research; (United States), Journal Name: Journal of Geophysical Research; (United States) Vol. 95:B9; ISSN 0148-0227; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

640107* -- Astrophysics & Cosmology-- Planetary Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ATMOSPHERES
COMPARATIVE EVALUATIONS
DISASTERS
DUSTS
ELECTRON DENSITY
EVALUATION
MARINER SPACE PROBES
MARS PLANET
PIONEER SPACE PROBES
PLANETARY ATMOSPHERES
PLANETS
SOLAR ACTIVITY
SOLAR WIND
SPACE VEHICLES
STORMS
VEHICLES
VENUS PLANET