Simulating the cloudy atmospheres of HD 209458 b and HD 189733 b with the 3D Met Office Unified Model
| Autor: | David S. Amundsen, Pascal Tremblin, Benjamin Drummond, Ian A. Boutle, Graham K. H. Lee, Nathan J. Mayne, Stefan Lines, Christiane Helling, Max Kerslake, James Manners, Jayesh M. Goyal, David M. Acreman |
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| Přispěvatelé: | University of Exeter, Maison de la Simulation (MDLS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut National de Recherche en Informatique et en Automatique (Inria)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Recherche en Informatique et en Automatique (Inria)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), University of St Andrews. School of Physics and Astronomy, University of St Andrews. St Andrews Centre for Exoplanet Science |
| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
MESH: radiative transfer
010504 meteorology & atmospheric sciences [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP] NDAS Library science FOS: Physical sciences Astrophysics 01 natural sciences Nexus (data format) Scattering 0103 physical sciences MESH: planets and satellites: gaseous planets Radiative transfer QB Astronomy [PHYS.MECA.MEFL]Physics [physics]/Mechanics [physics]/Fluid mechanics [physics.class-ph] 010303 astronomy & astrophysics QC Astrophysics::Galaxy Astrophysics QB 0105 earth and related environmental sciences Physics Earth and Planetary Astrophysics (astro-ph.EP) MESH: scattering numerical [Methods] European research MESH: hydrodynamics Astronomy and Astrophysics MESH: planets and satellites [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR] gaseous planets [Planets and satellites] QC Physics Space and Planetary Science Hydrodynamics MESH: methods: numerical atmospheres [Planets and satellites] Astrophysics::Earth and Planetary Astrophysics Astrophysics - Earth and Planetary Astrophysics MESH: atmospheres |
| Popis: | To understand and compare the 3D atmospheric structure of HD 209458 b and HD 189733 b, focusing on the formation and distribution of cloud particles, as well as their feedback on the dynamics and thermal profile. We couple the 3D Met Office Unified Model (UM), including detailed treatments of atmospheric radiative transfer and dynamics, to a kinetic cloud formation scheme. The resulting model self--consistently solves for the formation of condensation seeds, surface growth and evaporation, gravitational settling and advection, cloud radiative feedback via absorption and, crucially, scattering. Fluxes directly obtained from the UM are used to produce synthetic SEDs and phase curves. Our simulations show extensive cloud formation in both planets, however, cooler temperatures in the HD 189733 b result in higher cloud particle number densities. Sub-micron particles are suspended by vertical flows leading to extensive upper-atmosphere cloud cover. A combination of meridional advection and efficient cloud formation in cooler high latitude regions, result in enhanced cloud coverage for latitudes > 30 degrees and leads to a zonally banded structure for all our simulations. The cloud bands extend around the entire planet(s), as the temperatures, even on the day side, remain below the condensation temperature of silicates and oxides. Therefore, our simulated optical phase curve for HD 209458 b shows no `offset', in contrast to observations. Efficient scattering by cloud results an atmospheric cooling of up to 250K, and an advection-driven fluctuating cloud opacity causes temporal variability in the thermal emission. The inclusion of this fundamental cloud-atmosphere radiative feedback leads to significant differences with approaches neglecting these physical elements and suggests both a note of caution of interpretations neglecting such cloud feedback and scattering, and merits further study. 28 pages, 23 figures and accepted for publication in A&A |
| Databáze: | OpenAIRE |
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