Giant planet upper atmospheres have long been observed to be significantly hotter than expected. Magnetosphere-atmosphere coupling processes give rise to auroral emissions and enormous energy deposition near the magnetic poles, explaining high temperatures for narrow regions of the planet. However, global circulation models have difficulty redistributing auroral energy globally due to the strong Coriolis forces and ion drag. Heating by solar photons is insufficient at giant planets, and yet

more »

... r proposed processes, such as heating by waves originating from the lower atmosphere, also fail to explain the warm equatorial temperature. There remains no self-consistent explanation for measured non-auroral temperatures at present, mostly due to a lack of definitive observational constraints. Here, using high-resolution maps capable of tracing global temperature gradients at Jupiter, we show that upper-atmosphere temperatures decrease steadily from the aurora to the equator. During a period of enhanced auroral activity, likely driven by a coincident solar wind compression event, we also find a global increase in temperature accompanied by a high temperature planetary-scale structure that appears to emanate from the auroral region. These observations indicate that Jupiter's upper atmosphere is predominantly heated via the redistribution of auroral energy.