| Issue |
A&A
Volume 658, February 2022
|
|
|---|---|---|
| Article Number | A33 | |
| Number of page(s) | 10 | |
| Section | Planets and planetary systems | |
| DOI | https://doi.org/10.1051/0004-6361/202140778 | |
| Published online | 27 January 2022 | |
Planetary climate under extremely high vertical diffusivity★
1
Department of Atmospheric and Oceanic Sciences, School of Physics, Peking University,
Beijing
100871,
PR China
e-mail: junyang@pku.edu.cn
2
Now at the Department of Atmospheric and Oceanic Sciences, University of California,
Los Angeles,
CA
90095,
USA
Received:
10
March
2021
Accepted:
7
October
2021
Aims. Planets with large moon(s) or those in the habitable zone of low-mass stars may experience much stronger tidal force and tide-induced ocean mixing than that on Earth. Thus, the vertical diffusivity (or, more precisely, diapycnal diffusivity) on such planets, which represents the strength of vertical mixing in the ocean, would be greater than that on Earth. In this study, we explore the effects of extremely high diffusivity on the ocean circulation and surface climate of Earth-like planets in one asynchronous rotation orbit.
Methods. The response of planetary climate to 10 and 100 times greater vertical diffusivity than that found on Earth is investigated using a fully coupled atmosphere–ocean general circulation model. In order to perform a clear comparison with the climate of modern Earth, Earth’s orbit, land–sea configuration, and present levels of greenhouse gases are included in the simulations.
Results. We find that a larger vertical diffusivity intensifies the meridional overturning circulation (MOC) in the ocean, which transports more heat to polar regions and melts sea ice there. Feedback associated with sea ice, clouds, and water vapor act to further amplify surface warming. When the vertical diffusivity is 10 (100) times the present-day value, the magnitude of MOC increases by ≈3 (18) times, and the global-mean surface temperature increases by ≈4 °C (10 °C). This study quantifies the climatic effect of an extremely strong vertical diffusivity and confirms an indirect link between planetary orbit, tidal mixing, ocean circulation, and surface climate. Our results suggest a moderate effect of varying vertical ocean mixing on planetary climate.
Key words: astrobiology / Earth / planets and satellites: oceans / planets and satellites: atmospheres / planets and satellites: terrestrial planets
The data and code used in this article are available via: http://doi.org/10.5281/zenodo.5527297.
© ESO 2022
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.