Research project P4S/251/CONTEXT (Research action P4S)
Motivation
The ExoMars Trace Gas Orbiter’s NOMAD instrument has provided a wealth of information on the thermal structure and composition of the Martian atmosphere, as well as insights into transport processes driven by dust storms. Key questions remain about how lower-atmosphere phenomena, such as dust storms, thermal tides, and gravity waves, impact the upper atmosphere. We can use General Circulation Models (GCMs) to better understand these interactions, with NOMAD temperature, density, and composition measurements as a guide.
Objectives
This project aims to investigate the coupling of the upper and lower atmosphere of Mars through modelling and observations, using and improving the tools developed in the Planetary Atmospheres group at IASB.
The three main objectives of the project are to 1) Improve our understanding of the heating and cooling mechanisms in the upper atmosphere and the connections to the lower atmosphere; 2) Study the dynamic wave-driven coupling between the lower and upper atmosphere through GCM modelling and observations; 3) Enable the further investigation of atmospheric escape and airglow in the Martian atmosphere by bringing together lower and upper atmospheric chemistry.
Methods
We will use and improve the GEM-Mars GCM, which simulates the thermal structure, circulation, and composition of the Martian atmosphere, together with enhanced NOMAD retrievals of temperature, density, and composition.
Objective 1: Improve our retrieval of temperatures from NOMAD observations and our radiative transfer modelling of the upper atmosphere in the GCM, allowing joint analysis of model and data to build a better picture of upper-atmosphere thermal structure and its coupling to lower levels.
Objective 2: Refine how the model treats dust and other particles and use new data and analysis methods to spot patterns such as waves and unusual temperature structures that reveal how different atmospheric layers interact.
Objective 3: Extend our GCM chemical scheme for the upper atmosphere and use GCM output with NOMAD observations of airglow and trace gases to link lower-atmosphere composition and processes with those in the upper atmosphere.
Together, these objectives enhance our modelling, retrieval, and analysis tools, enabling a more complete understanding of connections across the Martian atmosphere.
