Vertically-resolved observations of Jupiter's quasi-quadrennial oscillation from 2012 to 2019

TL;DR

This study uses eight years of mid-infrared observations to analyze Jupiter's quasi-quadrennial oscillation, revealing a stable sinusoidal pattern with a notable phase shift in 2017 linked to a thermal anomaly.

Contribution

It provides the first detailed, vertically-resolved, long-term characterization of Jupiter's QQO and identifies a potential link between thermal anomalies and phase shifts.

Findings

QQO has a 4-year period with 7K amplitude at 13.5 mbar

In 2017, the QQO phase shifted by about 1 year

A thermal anomaly at 28°N may be linked to the phase shift

Abstract

Over the last eight years, a rich dataset of mid-infrared CH4 observations from the TEXES instrument at IRTF has been used to characterize the thermal evolution of Jupiter's stratosphere. These data were used to produce vertically-resolved temperature maps between latitudes of 50{\deg}S and 50{\deg}N, allowing us to track approximately two periods of Jupiter's quasi-quadrennial oscillation (QQO). During the first five years of observations, the QQO has a smooth sinusoidal pattern with a period of 4.0$\pm$0.2 years and an amplitude of 7$\pm$1 K at 13.5 mbar (our region of maximum sensitivity). In 2017, we note an abrupt change to this pattern, with the phase being shifted backwards by ~1 year. Searching for possible causes of this QQO delay, we investigated the TEXES zonally-resolved temperature retrievals and found that in May/June 2017, there was an unusually warm thermal anomaly located at a latitude of 28{\deg}N and a pressure of 1.2 mbar, moving westward with a velocity of 19$\pm$4 m/s. We suggest that there may be a link between these two events.