The quasiquadrennial oscillation of Jupiter's equatorial stratosphere

Abstract

A NEW 11-year record of Jupiter's stratospheric temperature¹ shows an equatorial temperature oscillation with an apparent period of 4–5 years. Here we compare this oscillation to two long-period oscillations of zonal winds in the Earth's equatorial stratosphere, and propose that the same mechanism—forcing by the stresses of vertically propagating waves—is responsible for the oscillations on both planets. Jupiter's temperature oscillation has been observed for slightly more than two cycles and closely resembles the temperature signatures of the Earth's semiannual oscillation and quasibiennial oscillation. If the mechanisms responsible for these oscillations are indeed similar, Jupiter's oscillation indicates that there is significant vertical momentum transport due to equatorially trapped atmospheric waves, and it may provide a means for probing the poorly understood process of the generation of these waves by convection^2,3.