Abstract

For decades, Martian general circulation models (GCMs) have struggled to reproduce observed ozone abundances, with even the most recent models underestimating ozone columns by approximately a factor of two. Many studies have explored the origin of this discrepancy, identifying only partial solutions that improve agreement at specific latitudes or seasons. The persistent mismatch has led to the widespread assumption that current Martian GCMs are missing a key physical or chemical process affecting the production, loss, or transport of ozone.

The ExoMars Trace Gas Orbiter (TGO) provides an unprecedented dataset: 3.5 Martian years of high-quality ozone columns and vertical profiles, spanning a wide range of seasons and atmospheric conditions. These observations offer a unique opportunity to characterise the Martian ozone cycle and systematically evaluate model performance.

In this presentation, I will first introduce the Martian atmosphere and its relevance for comparative planetology studies, and briefly review past and current missions to the Red Planet. I will then show how recent GCM simulations compare with observations and assess, using the TGO dataset, whether an additional process is indeed required to reconcile GCMs and observed ozone levels.