Fluctuations in the reversal of Jupiter’s stratospheric jet streams

Solar System planetary atmospheres, from the terrestrial planets to the giants, display a banded structure of winds and temperatures over a wide range of altitudes. The equatorial stratospheres of the Earth, Jupiter, and Saturn all exhibit a remarkable periodic oscillation of their temperatures (and therefore winds) with height, forced by waves produced by tropospheric meteorology far below. Earth's Quasi-Biennial Oscillation (QBO, thought to be regular with a ~28-month average period) and Saturn's Quasi-Periodic Equatorial Oscillation (QPO, with a ~15-year period) have recently been observed to experience severe disruptions in their periodicities and vertical structure as a consequence of atmospheric events occurring far from the equator. During these extreme events, waves injected additional angular momentum into their stratospheres, altering the regular signals of the QBO on Earth and the QPO on Saturn. Using three decades of infrared observations of Jupiter, we reveal for the rst time that its QQO can also be perturbed by strong tropospheric activity at the equator and at higher latitudes. Observations of Jupiter's stratospheric temperatures between 1980 and 2011 show two significantly difierent periods of the QQO, with a 5.7-year period between 1980 and 1990 and 3.9 years between 1996 and 2006. A constant 4- 5-year period (reported by previous studies) over 1980-2011 fails to reproduce either the observed stratospheric temperature oscillations or the odd behavior after 2007. Following the observed periodicities, local temperature minima were expected to be observed at the equator in 1992 and 2007. However, observations reveal the complete opposite, suggesting major disruption to the predicted QQO pattern. Unlike Earth's QBO, Jupiter's stratospheric oscillation appeared to lock into a new period entirely after the 1992 disruption, something never previously observed on any terrestrial or giant planet. This anomalous behavior coincided with dramatic planetary-scale disturbances observed in 1990-1992 and 2006-2007 in the equatorial and low-latitudes troposphere, which completely altered Jupiter's banded cloud morphology. Unlike on Saturn, where the QPO disruption was due to waves propagating equatorwards from the enormous hot stratospheric vortex seated at 40 deg N, the Jovian disruption is connected to waves generated by equatorial and non-equatorial meteorological sources within the ammonia cloud deck, indicating that disruptions in equatorial oscillations are not simply limited to giant storms like those on Saturn. This interconnectivity between the troposphere and stratosphere on the archetypal gas giant, whereby distant meteorology can severely disrupt the regular oscillations at high altitudes, provides valuable constraints on numerical atmospheric simulations and opens up a new window into the shared dynamics of terrestrial and giant-planet atmospheres.