The impact of convection on the climate of TRAPPIST-1e in global stretched-mesh simulations

Convective processes are crucial in shaping exoplanetary atmospheres but are computationally expensive to simulate directly. A novel technique of simulating moist convection, especially on tidally locked exoplanets such as those orbiting TRAPPIST-1, is to use a 3D general circulation model (GCM) with a global stretched mesh. This allows us to locally refine the model resolution to a km-scale and resolve deep convection without relying on parameterization. We explore the impact of explicit vs parameterized convection on the climate of TRAPPIST-1e, a confirmed rocky exoplanet in the habitable zone and a primary candidate for atmospheric characterization. We show allowing for explicit convection in a stretched-mesh simulation results primarily in changes in cloud distribution and precipitation on a planetary scale. Nevertheless, the overall climate state is close to that produced with parameterized convection and a non-stretched mesh. Additionally, these novel simulations shed more light on the bistability of the atmospheric circulation on TRAPPIST-1e. Our methodology opens an exciting and computationally feasible avenue for improving our understanding of fine-scale 3D mixing in exoplanetary atmospheres.