Atmospheric Convection Plays a Key Role in the Climate of Tidally Locked Terrestrial Exoplanets: Insights from High-resolution Simulations
Year: 2020
Type: article
Abstract: Using a 3D general circulation model (GCM), we investigate the sensitivity of the climate of tidally locked Earthlike exoplanets, Trappist-1e and Proxima Centauri b, to the choice of a convection parameterization. Compared to a mass-flux convection parameterization, a simplified convection adjustment parameterization leads to a >60% decrease of the cloud albedo, increasing the mean dayside temperature by . The representation of convection also affects the atmospheric conditions of the night side, via a change in planetary-scale wave patterns. As a result, using the convection adjustment scheme makes the nightside cold traps warmer by 17–36 K for the planets in our simulations. The day–night thermal contrast is sensitive to the representation of convection in 3D GCM simulations, so caution should be taken when interpreting emission phase curves. The choice of convection treatment, however, does not alter the simulated climate enough to result in a departure from habitable conditions, at least for the atmospheric composition and planetary parameters used in our study. The near-surface conditions both in the Trappist-1e and Proxima b cases remain temperate, allowing for an active water cycle. We further advance our analysis using high-resolution model experiments, in which atmospheric convection is simulated explicitly. Our results suggest that in a hypothetical global convection-permitting simulation, the surface temperature contrast would be higher than in the coarse-resolution simulations with parameterized convection. In other words, models with parameterized convection may overestimate the inter-hemispheric heat redistribution efficiency.
Source: The Astrophysical Journal
Authors: Denis E. Sergeev, F. Hugo Lambert, Nathan J. Mayne, Ian A. Boutle, James Manners, Krisztian Kohary
Institutions: University of Exeter, Met Office
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
SDG: Climate action
Open Access status: bronze
Awards: A comprehensive study of stars, disks and exoplanets, DiRAC-3 Operations 2019-2022 - Edinburgh, DiRAC-3 Operations 2019-2022 - Cambridge [2020-06 resubmission], The DiRAC 2.5x Facility, STFC DiRAC Project Office 2014-2017, Revealing the Structure of the Universe: From Extreme Gravity to Exoplanets, DiRAC-2 Datacentric support grant, DiRAC SMP Facility: The Structure of the Universe, DiRAC 2.5 Operations 2017-2020, A pathfinder project for a National AAAI, DiRAC-3 Operations 2019-2022 - Cambridge, Unveiling the Structure of the Universe, DiRAC Bridging Grant 2019 - Cambridge, DiRAC-2.5 DC - Operations 2017-2020, Dirac-3 Operations 2019-2022- Durham, Resources for DiRAC2 at HPCs, Dirac 2.5 Operations, DiRAC2.5 Operations: The DiRAC Project Office 2017-2020, DiRAC 2.5y Bridging Funding - UCL, Edinburgh DiRAC Resource Grant, The Structure of the Universe: Cosmology, Exoplanets and Lattice QCD, DiRAC2: 100 Tflop/s HPC cluster procurement, DiRAC SMP Facility: Revealing the Structure of the Universe, G7937591081, DiRAC Bridging Grant 2019, Software development support for DiRAC, G8962111125, DiRAC 2.5 Operations 2017-2020
OpenAlex ID: W3015457480