The rotational and divergent components of atmospheric circulation on tidally locked planets

Abstract

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- 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.

arXiv commentAccepted for publication in Proceedings of the National Academy of Sciences. 11 pages, 10 figures

References in corpus (50)

• Seven temperate terrestrial planets around the nearby ultracool dwarf star TRAPPIST-1
• ELODIE metallicity-biased search for transiting Hot Jupiters II. A very hot Jupiter transiting the bright K star HD189733
• Equatorial superrotation on tidally locked exoplanets
• Giant Planets at Small Orbital Distances
• STARRY: Analytic Occultation Light Curves
• Transitions in the cloud composition of hot Jupiters
• Discovery and Characterization of Transiting SuperEarths Using an All-Sky Transit Survey and Follow-up by the James Webb Space Telescope
• 3D climate modeling of close-in land planets: Circulation patterns, climate moist bistability and habitability
• VULCAN: an Open-Source, Validated Chemical Kinetics Python Code for Exoplanetary Atmospheres
• Modelling climate diversity, tidal dynamics and the fate of volatiles on TRAPPIST-1 planets
• Atmospheric Circulation of Hot Jupiters: Dayside-Nightside Temperature Differences
• Atmospheric Heat Redistribution on Hot Jupiters
• Atmospheric dynamics of Earth-like tidally locked aquaplanets
• Atmospheric Dynamics of Hot Exoplanets
• Increased Heat Transport in Ultra-Hot Jupiter Atmospheres Through H${}_2$ Dissociation/Recombination
• Observations of Exoplanet Atmospheres
• The Atmospheric Circulation of Ultra-hot Jupiters
• Demarcating circulation regimes of synchronously rotating terrestrial planets within the habitable zone
• The Transiting Exoplanet Community Early Release Science Program for JWST
• 3D modeling of GJ1214b's atmosphere: vertical mixing driven by an anti-Hadley circulation
• The Impact of Non-Uniform Thermal Structure on the Interpretation of Exoplanet Emission Spectra
• Atmospheric circulation of tidally locked exoplanets: II. Dual-band radiative transfer and convective adjustment
• 3D Structures of equatorial waves and the resulting superrotation in the atmosphere of a tidally locked hot Jupiter
• Atmospheric Regimes and Trends on Exoplanets and Brown Dwarfs
• Highlights in the Study of Exoplanet Atmospheres
• Global-mean Vertical Tracer Mixing in Planetary Atmospheres I: Theory and Fast-rotating Planets
• Vertical Tracer Mixing in Hot Jupiter Atmospheres
• The rotational and divergent components of atmospheric circulation on tidally locked planets
• Connecting the dots II: Phase changes in the climate dynamics of tidally locked terrestrial exoplanets
• Understanding and Mitigating Biases when Studying Inhomogeneous Emission Spectra with JWST
• Temperature Structure and Atmospheric Circulation of Dry, Tidally Locked Rocky Exoplanets
• Deciphering thermal phase curves of dry, tidally locked terrestrial planets
• Atmospheric Circulation of Exoplanets
• Linking the Climate and Thermal Phase Curve of 55 Cancri e
• 2.5-D retrieval of atmospheric properties from exoplanet phase curves: Application to WASP-43b observations
• Equatorial anti-rotating day side wind flow in WASP-43b elicited by deep wind jets?
• Global-mean Vertical Tracer Mixing in Planetary Atmospheres II: Tidally Locked Planets
• Wave-Mean Flow Interactions in the Atmospheric Circulation of Tidally Locked Planets
• A Significant Increase in Detection of High-Resolution Emission Spectra Using a Three-Dimensional Atmospheric Model of a Hot Jupiter
• On the Stability of Super-Earth Atmospheres
• Atmospheric convection plays a key role in the climate of tidally-locked terrestrial exoplanets: insights from high-resolution simulations
• THOR: A New and Flexible Global Circulation Model to Explore Planetary Atmospheres
• Connecting the dots: A versatile model for the atmospheres of tidally locked Super-Earths
• The influence of a sub-stellar continent on the climate of a tidally-locked exoplanet
• Phase Offsets and the Energy Budgets of Hot Jupiters
• 2D Retrieval Frameworks for Hot Jupiter Phase Curves
• THOR 2.0: Major Improvements to the Open-Source General Circulation Model
• A More Informative Map: Inverting Thermal Orbital Phase and Eclipse Lightcurves of Exoplanets
• Utility of the Weak Temperature Gradient Approximation for Earth-Like Tidally Locked Exoplanets
• The Equatorial Jet Speed on Tidally Locked Planets: I -- Terrestrial Planets

Cited by in corpus (43)

• The rotational and divergent components of atmospheric circulation on tidally locked planets
• The TRAPPIST-1 Habitable Atmosphere Intercomparison (THAI). Part II: Moist Cases -- The Two Waterworlds
• The TRAPPIST-1 Habitable Atmosphere Intercomparison (THAI). Part I: Dry Cases -- The fellowship of the GCMs
• No umbrella needed: Confronting the hypothesis of iron rain on WASP-76b with post-processed general circulation models
• Super-Earths and Earth-like Exoplanets
• Hot Jupiter Diversity and the Onset of TiO/VO Revealed by a Large Grid of Non-Grey Global Circulation Models
• Diagnosing limb asymmetries in hot and ultra-hot Jupiters with high-resolution transmission spectroscopy
• Interior dynamics of super-Earth 55 Cancri e
• ExoPlaSim: Extending the Planet Simulator for Exoplanets
• Lightning-induced chemistry on tidally-locked Earth-like exoplanets
• Transmission strings: a technique for spatially mapping exoplanet atmospheres around their terminators
• Temperature Structures Associated with Different Components of the Atmospheric Circulation on Tidally Locked Exoplanets
• Sporadic Spin-Orbit Variations in Compact Multi-planet Systems and their Influence on Exoplanet Climate
• Longitudinally asymmetric stratospheric oscillation on a tidally locked exoplanet
• Dynamics and Clouds in Planetary Atmospheres from Telescopic Observations
• Global Chemical Transport on Hot Jupiters: Insights from 2D VULCAN photochemical model
• Convective shutdown in the atmospheres of lava worlds
• Atmospheric Dynamics of a Near Tidally Locked Earth-Size Planet
• Stratospheric dayside-to-nightside circulation drives the 3-D ozone distribution on synchronously rotating rocky exoplanets
• Atmospheric dynamics of temperate sub-Neptunes. Part I: dry dynamics
• Temperature-chemistry coupling in the evolution of gas giant atmospheres driven by stellar flares
• Traveling planetary-scale waves cause cloud variability on tidally locked aquaplanets
• 3D simulations of TRAPPIST-1e with varying CO2, CH4 and haze profiles
• Atmospheric Overturning Circulation on Dry, Tidally-locked Rocky Planets is Mainly Driven by Radiative Cooling
• Multiple moist climate equilibrium states on arid rocky M-dwarf planets: A last-saturation tracer analysis
• Geodynamics of super-Earth GJ 486b
• Examining NHD vs QHD in the GCM THOR with non-grey radiative transfer for the hot Jupiter regime
• 3D Global climate model of an exo-Venus: a modern Venus-like atmosphere for the nearby super-Earth LP 890-9 c
• Meta-modelling the climate of dry tide locked rocky planets
• Lorenz Energy Cycle: Another Way to Understand the Atmospheric Circulation on Tidally Locked Terrestrial Planets
• Global flow regimes of hot Jupiters
• Spitzer phase curve observations and circulation models of the inflated ultra-hot Jupiter WASP-76b
• A novel metric for assessing climatological surface habitability
• The impact of water clouds on the prospective emission spectrum of Teegarden's Star b as observed by LIFE
• Flows, Circulations, and Energy Transport in the Outer and Deep Atmospheres of Synchronous and Non-synchronous Hot Jupiters
• The Feasibility of Asynchronous Rotation via Thermal Tides for Diverse Atmospheric Compositions
• The Most Common Habitable Planets III -- Modeling Temperature Forcing and Surface Conditions on Rocky Exoplanets and Exomoons
• Simulations of idealised 3D atmospheric flows on terrestrial planets using LFRic-Atmosphere
• Patchy nightside clouds on ultra-hot Jupiters: General Circulation Model simulations with radiatively active cloud tracers
• A 3D model simulation of hydrogen chloride photochemistry on Mars: Comparison with satellite data
• Formulation and evaluation of ocean dynamics problems as optimization problems for quantum annealing machines
• Climate uncertainties caused by unknown land distribution on habitable M-Earths
• Assessing the Climate and Habitability of Tidally Locked Rocky Exoplanets