Bistability of the Atmospheric Circulation on TRAPPIST-1e

Abstract Using a 3D general circulation model, we demonstrate that confirmed rocky exoplanet and primary observational target, TRAPPIST-1e presents an interesting case of climate bistability. We find the atmospheric on can exist in two distinct regimes for 1 bar nitrogen-dominated atmosphere. One is characterized by single strong equatorial prograde jet large day–night temperature difference; other pair mid-latitude jets relatively small contrast. The regime appears to be highly sensitive model setup, including initial surface boundary conditions, as well physical parameterizations convection cloud radiative effects. focus emergence during early stages simulations show bistability associated with delicate balance between zonally asymmetric heating, mean overturning circulation, baroclinic instability. relative strength these processes places GCM different branches evolution dynamics. resulting steady states have consistent differences amount water content clouds, affecting absorption bands continuum level transmission spectrum, although they are too detected current technology. Nevertheless, this affects temperature, especially night side planet, understanding dynamics highlights uncertainty results, motivating more multimodel studies.