EGU2020-14498, updated on 09 Jan 2023
https://doi.org/10.5194/egusphere-egu2020-14498
EGU General Assembly 2020
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Explanation for the increase in high altitude water on Mars observed by NOMAD during the 2018 global dust storm

Lori Neary1, Frank Daerden1, Shohei Aoki1, James Whiteway2, Robert Todd Clancy3, Michael Smith4, Sébastien Viscardy1, Justin Erwin1, Ian Thomas1, Ann Carine Vandaele1, and the Members of the NOMAD Team*
Lori Neary et al.
  • 1Royal Belgian Institute for Space Aeronomy, Planetary Aeronomy, Brussels, Belgium (lori.neary@aeronomie.be)
  • 2Centre for Research in Earth and Space Science, York University, Toronto, ON, Canada
  • 3Space Science Institute, Boulder, CO, USA
  • 4NASA Goddard Space Flight Center, Greenbelt, MD, USA
  • *A full list of authors appears at the end of the abstract

Using the GEM-Mars three-dimensional general circulation model (GCM), we examine the mechanism responsible for the enhancement of water vapour in the upper atmosphere as measured by the Nadir and Occultation for MArs Discovery (NOMAD) instrument onboard ExoMars Trace Gas Orbiter (TGO) during the 2018 global dust storm on Mars.

Experiments with different prescribed vertical profiles of dust show that when more dust is present higher in the atmosphere, the temperature increases and the amount of water ascending over the tropics is not limited by saturation until reaching heights of 70-100 km. The warmer temperatures allow more water to ascend to the mesosphere. The simulation of enhanced high-altitude water abundances is very sensitive to the vertical distribution of the dust prescribed in the model.

The GEM-Mars model includes gas-phase photochemistry, and these simulations show how the increased water vapour over the 40-100 km altitude range results in the production of high-altitude atomic hydrogen which can be linked to atmospheric escape.

Members of the NOMAD Team:

G. Villanueva, G. Liuzzi, M. Crismani, M. J. Wolff, S. Lewis, J. Holmes, M. Patel, M. Giuranna, C. Depiesse, A. Piccialli, S. Robert, L. Trompet, Y. Willame, B. Ristic

How to cite: Neary, L., Daerden, F., Aoki, S., Whiteway, J., Clancy, R. T., Smith, M., Viscardy, S., Erwin, J., Thomas, I., and Vandaele, A. C. and the Members of the NOMAD Team: Explanation for the increase in high altitude water on Mars observed by NOMAD during the 2018 global dust storm, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-14498, https://doi.org/10.5194/egusphere-egu2020-14498, 2020.

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