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The Effects of Solar Cycle Variability on D and H in the Upper Atmosphere of Mars
  • +8
  • Majd Mayyasi,
  • John Clarke,
  • Jean-Yves Chaufray,
  • Stephen Bougher,
  • David Kass,
  • Geronimo Villanueva,
  • Franck Montmessin,
  • Justin Deighan,
  • Sonal Jain,
  • Nicholas Schneider,
  • Bruce Jakosky
Majd Mayyasi
Boston University

Corresponding Author:majdm@bu.edu

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John Clarke
Boston University
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Jean-Yves Chaufray
LATMOS/IPSL, UVSQ Université Paris-Saclay, Sorbonne Université
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Stephen Bougher
Climate and Space Sciences and Engineering Department
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David Kass
NASA Jet Propulsion Laboratory, California Institute of Technology
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Geronimo Villanueva
NASA Goddard Space Flight Center
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Franck Montmessin
Service d'aéronomie du CNRS
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Justin Deighan
Laboratory for Atmospheric and Space Physics
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Sonal Jain
Laboratory for Atmospheric and Space Physics
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Nicholas Schneider
Univ Colorado
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Bruce Jakosky
University of Colorado Boulder
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The upper atmosphere of Mars is directly affected by solar activity and the resulting solar irradiance impinging upon it. Variations in solar forcing can affect the rate at which atmospheric species escape from the planetary system. Remotely sensed observations of the upper atmosphere of Mars have been made during solar activity extrema of Solar Cycles 22 and 24. These observations were made of D and H Lyman-a emissions using the Mars Atmosphere and Volatile Evolution (MAVEN) mission and the Hubble Space Telescope (HST) high resolution spectrographs. Data obtained from the two missions are analyzed and used to derive densities and escape rates of D and H from the martian upper atmosphere. The results show that the properties of these two water-spawned atoms vary with solar cycle, and display significant inter-annual variability, mainly due to variations in atmospheric temperature. The findings suggest that cooler atmospheric temperatures due to reduced solar EUV flux may enhance the abundance of H atoms in the upper atmosphere of Mars, yet this does not increase their escape rates.