# MarTIM

*Version 2.0.4 (23th April 2013)*

*Originally developed by T. Moffat-Griffin*

*Subsequently modified (and coupled to kinetic model) by W. P. Nicholson*

*Kinetic model provided by J. Lilenstein*

MarTIM is University College Londons (UCL) Mars thermosphere and ionosphere general circulation model (GCM). It is a finite difference model, which solves the coupled non-linear Navier-Stokes equations of continuity and momentum as well as an energy equation. Calculations are conducted on a fixed co-rotating grid of variable size in the pressure coordinate system.

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From its lower boundary of 0.883 Pa (∼60 km) to its upper boundary
of 9.9×10⁻⁸ Pa (∼200-350 km), it evaluates the main sources of solar
forcing (EUV/UV and IR absorption) while self-consistently determining
the composition of four of the major gas species, CO₂, N₂, CO and
O. These four major gases are mutually diffused throughout the model
in a typical run.

MarTIMs 0.883 Pa lower boundary can be coupled to the Mars Climate
Database (MCD v4.3) developed by the University of Oxford, the Open
University and Laboratoire de Météorologie Dynamique. This database
of GCM results provides MarTIM a physically self-consistent lower
boundary derived from multiple runs of the aforementioned circulation
models. Consequently the effects of dust storms, non-migrating tides
and the influence of Martian topography can be studied by prescription
of MarTIMs lower boundary.

The
publication Nicholson
et al., 2009 (doi:10.1111/j.1365-2966.2009.15463.x), published
results from a collaboration with Dr Jean Lilensten, Laboratoire de
Planétologie de Grenoble. Here, MarTIM was coupled to a more
sophisticated ionosphere model that solved a one-dimensional kinetic
Boltzmann transport equation for the suprathermal population of
electrons present in the Martian ionosphere. This self-consistently
described an ionosphere produced by both primary photoionisation) and
secondary ionisation (suprathermal electron propagation).

A more complete description of the entire model and detailed
numerical experiments conducted towards the PhD degree Nicholson,
W. P. 2011, is available to download
from http://discovery.ucl.ac.uk/1310428/.