The GEM-Mars model
To study the Martian atmosphere, large three-dimensional computer models are required, incorporating atmospheric dynamics and chemistry, similar to large weather and climate models on Earth. BIRA-IASB developed such a model, starting from a Canadian weather model for Earth. This model, GEM-Mars, is only the second of its kind in the world.
Mars atmospheric chemistry
The atmosphere of Mars consists of 96% carbon dioxide (CO2). The north polar ice cap releases water vapor (H2O) every year during summer.
The chemical interactions between the photolysis products of CO2 and H2O lead to the formation of other species, such as ozone (O3) and hydrogen peroxide (H2O2). Both CO2 and H2O on Mars undergo a complex cycle as they can be frozen into ice clouds or surface ice.
Models for Mars need to include all these complicated interactions.
Recent results and future plans
An extensive evaluation of the GEM-Mars model was performed by comparing to the most complete datasets for the species that have been observed on Mars with wide coverage:
- airglow from O2
The results are very good and bring GEM-Mars to the state of the art. Now the model will be applied for the analysis and interpretation of the observations from the NOMAD instrument on the ExoMars Trace Gas Orbiter, which started its investigation of the composition of the Mars atmosphere in April 2018.