MAVEN/IUVS Stellar Occultation Measurements of Mars Atmospheric Structure and Composition

H. Gröller, F. Montmessin, R. V. Yelle, F. Lefèvre, F. Forget, N. M. Schneider, T. T. Koskinen, J. Deighan, S. K. Jain

Research output: Contribution to journalArticlepeer-review

19 Scopus citations

Abstract

The Imaging UltraViolet Spectrograph (IUVS) instrument of the Mars Atmosphere and Volatile EvolutioN (MAVEN) mission has acquired data on Mars for more than one Martian year. During this time, beginning with March 2015, hundreds of stellar occultations have been observed, in 12 dedicated occultation campaigns, executed on average every 2 to 3 months. The occultations cover the latitudes from 80°S to 75°N and the full range longitude and local times with relatively sparse sampling. From these measurements we retrieve CO2, O2, and O3 number densities as well as temperature profiles in the altitude range from 20 to 160 km, covering 8 orders of magnitude in pressure from ∼2 × 101 to ∼4 × 10−7 Pa. These data constrain the composition and thermal structure of the atmosphere. The O2 mixing ratios retrieved during this study show a high variability from 1.5 × 10−3 to 6 × 10−3; however, the mean value seems to be constant with solar longitude. We detect ozone between 20 and 60 km. In many profiles there is a well-defined peak between 30 and 40 km with a maximum density of 1–2 ×109 cm−3. Examination of the vertical temperature profiles reveals substantial disagreement with models, with observed temperatures both warmer and colder than predicted. Examination of the altitude profiles of density perturbations and their variation with longitude shows structured atmospheric perturbations at altitudes above 100 km that are likely nonmigrating tides. These perturbations are dominated by zonal wave numbers 2 and 3 with amplitudes greater than 45%.

Original languageEnglish (US)
Pages (from-to)1449-1483
Number of pages35
JournalJournal of Geophysical Research: Planets
Volume123
Issue number6
DOIs
StatePublished - Jun 2018

Keywords

  • MAVEN/IUVS stellar occultations
  • atmospheric composition and structure
  • molecular oxygen
  • ozone
  • temperature profiles
  • waves/tides detection

ASJC Scopus subject areas

  • Geophysics
  • Forestry
  • Oceanography
  • Aquatic Science
  • Ecology
  • Water Science and Technology
  • Soil Science
  • Geochemistry and Petrology
  • Earth-Surface Processes
  • Atmospheric Science
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science
  • Palaeontology

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