Abstract
Mars atmospheric modelling has come far in the past two decades, with increased missions
expanding our observational capabilities drastically. These observations are allowing us to
develop increasingly accurate Martian Global Climate Models (hereafter; GCMs) (Forget
et al., 1999; Read, Lewis and Mulholland, 2015; Martínez et al., 2017). There are currently
several well-established GCMs that already model Mars’ atmosphere, including (but not
limited to) the LMDs Mars GCM, NASAs AMES Mars model and OpenMARS.
Here we describe the usage and first climate results from our adaptation of the Met Offices
Unified Model (hereafter; UM), one of the most sophisticated Earth GCMs already used for
modelling exoplanets, for a Martian climate. By adapting established climate schemes used
for the study of Earth within the GCM (e.g. atmospheric dust, wind, atmospheric composition,
etc.) to Mars’ characteristics, we can create a highly sophisticated Mars model (e.g. high
spatial resolution, dynamic dust scheme). Our simulations will be verified by comparison
with existing Mars GCMs. The key parameters incorporated into our GCM will include:
1. Radiatively active dust
2. Orography
3. Martian orbital parameters
4. Atmospheric composition and pressure
5. Atmospheric H2 O
6. CO2 ice
In this presentation I will detail the different schemes incorporated into the UM key to
simulating a Mars climate, then describe the processes used to implement them into the UM.
We will then showcase the different scenarios of Mars’ climate we have introduced and their
subsequent effects on other climate parameters (e.g. increased pressure and how it changes
temperature). I will finish by showing the verification process we used and comparisons to
other existing models.
Future of the project: A verified Mars-UM will then be used to investigate the relationship
that key climate variables have to each other. By forcing exaggerated changes in targeted
key parameters (e.g. doubling average surface pressure or increasing atmospheric moisture
content), we can then investigate the secondary effects these changes have on other parameters
in the Martian climate (e.g. change in temperature or dust mixing ratios). This study will
help discern the importance and relative influence of Mars’ key parameters, this will in-turn
provide insight for future areas of research and development.
This study is part of a Masters-by-research project.

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Figur 1: Overview 3D plot of an example output during Southern summer (Ls=260°).
Included is an extracted regional dust layer as an isosurface, free wind vectors at 1km
height (arrows) and an exaggerated orography (scaled up in this image by a factor of 30 to
highlight extremities). Higher resolution GIF and code available at https://github.com/
dannymcculloch

Acknowledgements:
This study has required a variety of skillsets due to the many schemes involved, to this the
authors would like to thank James Manners and the Met Office team for their assistance. We
would also like to thank Ehouarn Millour from the LMD for the assistance with providing
technical assistance when using their Mars climate Database. Lastly, we would like to
thank the Exeter Exoplanet Theory Group (EETG, exoclimatology.com) Patrick McGuire
(University of Reading) for their technical assistance, acting as a springboard for ideas and
for their input and encouragement throughout the project.

References:
Forget, F. et al. (1999) ‘Improved general circulation models of the Martian atmosphere
from the surface to above 80 km’, Journal of Geophysical Research E: Planets, 104(E10), pp.
24155–24175. doi: 10.1029/1999JE001025.
Hébrard, E. et al. (2012) ‘An aerodynamic roughness length map derived from extended
Martian rock abundance data’, Journal of Geophysical Research E: Planets, 117(4), p. 4008.
doi: 10.1029/2011JE003942.
Martínez, G. M. et al. (2017) ‘The Modern Near-Surface Martian Climate: A Review of
In-situ Meteorological Data from Viking to Curiosity’, Space Science Reviews, 212(1–2),
pp. 295–338. doi: 10.1007/s11214-017-0360-x.
Read, P. L., Lewis, S. R. and Mulholland, D. P. (2015) ‘The physics of Martian weather and climate: A review’, Reports on Progress in Physics, 78(12). doi: 10.1088/00344885/78/12/125901.

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