Long‐Term Variations of Jupiter's Stratospheric Planetary Waves Modulated by the Quasi‐Quadrennial Oscillation

Abstract Planetary wave activity on Jupiter has been consistently observed since the Voyager mission. This study uses NASA Infrared Telescope Facility 7.6–7.9 μm long‐term ground‐based observations from 1984 to 2011 and global maps from the Cassini flyby in November and December 2000 to analyze Jupiter's stratospheric planetary wave activity. The dominant waves are characterized by zonal wavenumbers 7 and 10, located around 20°N, with a wavenumber‐10 wave traveling westward at a 10‐day oscillation period and a phase speed of −47 m/s, as identified by Cassini. The amplitudes of both waves exhibit a long‐term variation, correlated with vertical wind shear and anti‐correlated with equatorial brightness temperature. Jupiter's quasi‐quadrennial oscillation (QQO) may influence this process by modifying extratropical wind shear, thus the vertical waveguide, ultimately contributing to the observed wave amplitude. The interactions among the QQO, mean flow, and wave activities can significantly impact Jupiter's stratosphere.