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Vertical aerosol distribution and mesospheric clouds from ExoMars UVIS
  • +12
  • Paul Michael Streeter,
  • Graham Sellers,
  • Michael J. Wolff,
  • J.P. Mason,
  • Manish R Patel,
  • Stephen Lewis,
  • James Andrew Holmes,
  • Frank W. Daerden,
  • Ian Richard Thomas,
  • Bojan Ristic,
  • Yannick Willame,
  • Cédric Depiesse,
  • Ann Carine Vandaele,
  • Giancarlo Bellucci,
  • José Juan López-Moreno
Paul Michael Streeter
Open University

Corresponding Author:paul.streeter@open.ac.uk

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Graham Sellers
The Open University
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Michael J. Wolff
Space Science Institute
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J.P. Mason
Open University
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Manish R Patel
The Open University
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Stephen Lewis
Open University
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James Andrew Holmes
Open University
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Frank W. Daerden
Royal Belgian Institute for Space Aeronomy BIRA-IASB
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Ian Richard Thomas
Belgian Institute for Space Aeronomy
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Bojan Ristic
Royal Belgian Institute for Space Aeronomy
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Yannick Willame
Belgian Institute For Space Aeronomy
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Cédric Depiesse
Royal Belgian Institute for Space Aeronomy
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Ann Carine Vandaele
Royal Belgian Institute for Space Aeronomy
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Giancarlo Bellucci
Institute for Space Astrophysics and Planetology
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José Juan López-Moreno
Instituto de Astrofisica de Andalucia, IAA-CSIC
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Abstract

The vertical opacity structure of the martian atmosphere is important for understanding the distribution of ice (water and carbon dioxide) and dust. We present a new dataset of extinction opacity profiles from the NOMAD/UVIS spectrometer aboard the ExoMars Trace Gas Orbiter, covering one and a half Mars Years (MY) including the MY 34 Global Dust Storm and several regional dust storms. We discuss specific mesospheric cloud features and compare with existing literature and a Mars Global Climate Model (MGCM) run with data assimilation. Mesospheric opacity features, interpreted to be water ice, were present during the global and regional dust events and correlate with an elevated hygropause in the MGCM, providing further evidence for the role of regional dust storms in driving atmospheric escape as reported elsewhere. The season of the dust storms also had an apparent impact on the resulting lifetime of the cloud features, with events earlier in the dusty season correlating with longer-lasting mesospheric cloud layers. Mesospheric opacity features were also present during the dusty season even in the absence of regional dust storms, and interpreted to be water ice based on previous literature. The assimilated MGCM temperature structure agreed well with the UVIS opacities, but the MGCM opacity field struggled to reproduce mesospheric ice features, suggesting a need for further development of water ice parameterizations. The UVIS opacity dataset offers opportunities for further research into the vertical aerosol structure of the martian atmosphere, and for validation of how this is represented in numerical models.