气候变化领域集成服务门户(CCPortal): The rotational and divergent components of atmospheric circulation on tidally locked planets

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DOI	10.1073/pnas.2022705118
	The rotational and divergent components of atmospheric circulation on tidally locked planets
	Hammond M.; Lewis N.T.
发表日期	2021
ISSN	00278424
卷号	118 期号:13
英文摘要	Tidally locked exoplanets likely host global atmospheric circulations with a superrotating equatorial jet, planetary-scale stationary waves, and thermally driven overturning circulation. In this work, we show that each of these features can be separated from the total circulation by using a Helmholtz decomposition, which splits the circulation into rotational (divergence-free) and divergent (vorticity-free) components. This technique is applied to the simulated circulation of a terrestrial planet and a gaseous hot Jupiter. For both planets, the rotational component comprises the equatorial jet and stationary waves, and the divergent component contains the overturning circulation. Separating out each component allows us to evaluate their spatial structure and relative contribution to the total flow. In contrast with previous work, we show that divergent velocities are not negligible when compared with rotational velocities and that divergent, overturning circulation takes the form of a single, roughly isotropic cell that ascends on the day side and descends on the night side. These conclusions are drawn for both the terrestrial case and the hot Jupiter. To illustrate the utility of the Helmholtz decomposition for studying atmospheric processes, we compute the contribution of each of the circulation components to heat transport from day side to night side. Surprisingly, we find that the divergent circulation dominates day–night heat transport in the terrestrial case and accounts for around half of the heat transport for the hot Jupiter. The relative contributions of the rotational and divergent components to day–night heat transport are likely sensitive to multiple planetary parameters and atmospheric processes and merit further study. © 2021 National Academy of Sciences. All rights reserved.
英文关键词	Atmospheric circulation; Exoplanets; Helmholtz decomposition
语种	英语
scopus关键词	article; astronomy; decomposition; heat; night; simulation; velocity
来源期刊	Proceedings of the National Academy of Sciences of the United States of America
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/180101
作者单位	Department of the Geophysical Sciences, University of Chicago, Chicago, IL 60637, United States; Atmospheric, Oceanic and Planetary Physics, Clarendon Laboratory, University of Oxford, Oxford, OX1 3PU, United Kingdom
推荐引用方式 GB/T 7714	Hammond M.,Lewis N.T.. The rotational and divergent components of atmospheric circulation on tidally locked planets[J],2021,118(13).
APA	Hammond M.,&Lewis N.T..(2021).The rotational and divergent components of atmospheric circulation on tidally locked planets.Proceedings of the National Academy of Sciences of the United States of America,118(13).
MLA	Hammond M.,et al."The rotational and divergent components of atmospheric circulation on tidally locked planets".Proceedings of the National Academy of Sciences of the United States of America 118.13(2021).