The Mars atmosphere Global Climate Model (GCM) developed at the Laboratoire de Météorologie Dynamique in collaboration with several teams in Europe (LATMOS, University of Oxford, The Open University, the Instituto de Astrofisica de Andalucia), and with the support of ESA and CNES is currently used for many kind of applications. Our primary objective is to predict all details of the Mars Climate system, including the dust, water, CO 2 and photochemical cycles from the surface to the exobase, yet only on the basis of universal equations. In practice, to simulate a given year, we still have to assume a daily map of column dust opacity (See Montabone et al., this issue), but otherwise the model is almost free of other forcing (including to predict the dust vertical distribution). 2013 was an important milestone for the project since it concluded a long series of model development defined on the basis of the analysis of the Mars Climate Database version 4, released in 2005 using a previous version of our GCM (Forget et al. 2006). Key improvements As documented in the previous edition of the Mars Atmosphere Modeling and Observation Workshop, and in the per-review literature:  Improved dynamical core for the polar atmosphere  Improvements of Mars surface fields (albedo and thermal inertia map)  Inclusion of subsurface water ice in the CO 2 ice cap energy balance, and improved tuning of the CO 2 cycle  Improved parametrizations of convection and near surface turbulence, using a thermal plume model This thermal plume model is coupled to surface layer parameterizations taking into account stability and turbulent gustiness to calculate surface-atmosphere fluxes (Colaitis et al. 2013)  Improvement of the representation of the airborne dust (Madeleine et al. 2011) based on a " semi-interactive " two moments dust transport scheme to predict the dust vertical distribution and the 3D variation of dust particle radii, coupled to improved radiative transfer calculations