Abstract
The temperatures of giant-planet upper atmospheres at mid- to low latitudes are measured to be hundreds of degrees warmer than simulations based on solar heating alone can explain. Modelling studies that focus on additional sources of heating have been unable to resolve this major discrepancy. Equatorward transport of energy from the hot auroral regions was expected to heat the low latitudes, but models have demonstrated that auroral energy is trapped at high latitudes, a consequence of the strong Coriolis forces on rapidly rotating planets. Wave heating, driven from below, represents another potential source of upper-atmospheric heating, though initial calculations have proven inconclusive for Jupiter, largely owing to a lack of observational constraints on wave parameters. Here we report that the upper atmosphere above Jupiter's Great Red Spot--the largest storm in the Solar System--is hundreds of degrees hotter than anywhere else on the planet. This hotspot, by process of elimination, must be heated from below, and this detection is therefore strong evidence for coupling between Jupiter's lower and upper atmospheres, probably the result of upwardly propagating acoustic or gravity waves.
Highlights
Measured upper-atmospheric, mid-to-low latitude temperatures of the giant planets are hundreds of degrees warmer than models based on solar heating alone can explain[1,2,3,4]
Our results indicate that the lower atmosphere may yet play an important role in resolving the giant planet ‘energy crisis’
The spectrometer slit was aligned along the rotational axis in the north-south direction at local noon
Summary
J.O’D. collected, analysed and interpreted the data and wrote the paper. L.M. greatly assisted in the data reduction, analysis, interpretation and writing of the paper. T.S. helped with the analysis and interpretation of the data. H.M. assisted in the collection and reduction of data, and provided computer code necessary for the analysis of data. All authors provided comments on the manuscript
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