Suchergebnisse

This is the author accepted manuscript. ; Data accessibility: All our GCM THAI data are permanently available for download here: https://ckan.emac.gsfc.nasa.gov/organization/thai, with variables described for each dataset. If you use these data please cite the current paper and add the following statement: "THAI data have been obtained from https://ckan.emac.gsfc.nasa.gov/organization/thai, a data repository of the Sellers Exoplanet Environments Collaboration (SEEC), which is funded in part by the NASA Planetary Science Divisions Internal Scientist Funding Model." Scripts to process the THAI data are available on GitHub: https://github.com/projectcuisines ; With the commissioning of powerful, new-generation telescopes such as the JWST and the ground-based ELTs, the first characterization of a high-molecular-weight atmosphere around a temperate rocky exoplanet is imminent. Atmospheric simulations and synthetic observables of target exoplanets are essential to prepare and interpret these observations. Here we report the results of the first part of the THAI (TRAPPIST-1 Habitable Atmosphere Intercomparison) project, which compares 3D numerical simulations performed with four state-of-the-art Global Climate Models (ExoCAM, LMD-Generic, ROCKE-3D, Unified Model) for the potentially habitable target TRAPPIST-1e. In this first part, we present the results of dry atmospheric simulations. These simulations serve as a benchmark to test how radiative transfer, subgrid-scale mixing (dry turbulence and convection) and large-scale dynamics impact the climate of TRAPPIST-1e and consequently the transit spectroscopy signature as seen by JWST. To first order, the four models give results in good agreement. The inter-model spread in the global mean surface temperature amounts to 7K (6K) for the N2-dominated (CO2-dominated, respectively) atmosphere. The radiative fluxes are also remarkably similar (inter-model variations less than 5%), from the surface (1bar) up to atmospheric pressures ∼5millibar. Moderate differences between the models appear in the atmospheric circulation pattern (winds) and the (stratospheric) thermal structure. These differences arise between the models from (1) large scale dynamics because TRAPPIST-1e lies at the tipping point between two different circulation regimes (fast and Rhines rotators) in which the models can be alternatively trapped; and (2) parameterizations used in the upper atmosphere such as numerical damping. ; UK Research and Innovation ; Science and Technology Facilities Council ; European Union Horizon 2020 ; Leverhulme Trust ; NASA