EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Atmospheric phenomena affecting the methane lifetime on Mars

John Lee Grenfell1, Fabian Wunderlich1,2, Miriam Sinnhuber3, Konstantin Herbst4, Markus Scheucher2, Stefanie Gebauer1, and Heike Rauer1,2,5
John Lee Grenfell et al.
  • 1DLR, Inst. for Planetary Research, Extrasolar Planets and Atmospheres (EPA), Berlin, Germany (
  • 2Zentrum für Astronomie und Astrophysik (ZAA), Technische Universität Berlin (TUB)
  • 3Institute for Meteorology and Climate Research, Karlsruhe Institute of Technologie (KIT)
  • 4Institute of Experimental and Applied Physics, Extraterrestrial Physics Kiel University (CAU)
  • 5Institut für Geologische Wissenschaften, Freie Universität Berlin (FUB)

We investigate a range of atmospheric phenomena concerning their potential to address the Martian methane lifetime discrepancy. This refers to the over-estimate of the modelled lifetimes compared to observations by a factor of up to six hundred. We apply a newly developed atmospheric photochemical model where we vary in a Monte Carlo approach the chemical rate and Eddy mixing coefficients within their current uncertainties. We also investigate the effect of air shower events due to galactic cosmic rays and solar cosmic rays. Our results suggest that the current uncertainty in chemical rates and transport together with seasonal changes in the water column can likely account for up to a factor of about thirty in the Mars methane lifetime discrepancy whereas the air shower effects are likely to be of secondary importance.

How to cite: Grenfell, J. L., Wunderlich, F., Sinnhuber, M., Herbst, K., Scheucher, M., Gebauer, S., and Rauer, H.: Atmospheric phenomena affecting the methane lifetime on Mars, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-15442,, 2021.

Corresponding presentation materials formerly uploaded have been withdrawn.