Spatial distribution of visible lightning on Jupiter

Abstract

SPACECRAFT observations have provided evidence for the existence of lightning on Venus^1–3, Jupiter^4,5, Saturn^6,7 and Uranus⁸. Little is known, however, about the global distribution of lightning on these planets because of the limited spatial resolution and areal coverage of these previous detections, which have principally involved radio-frequency measurements. Two long-exposure images obtained by the Voyager 1 spacecraft of a small area on the nightside of Jupiter have provided the only previously studied imaging observations of lightning on another planet^9,10. Here we present an analysis of all suitable Voyager images of Jupiter and evaluate the horizontal spatial distribution of visible lightning over most of one hemisphere. Essentially all the detectable activity is confined to very narrow latitude bands at 13.5° N and 49° N. The active regions at 49° N are the brightest, most numerous and periodic in longitude. Activity at this latitude is long-lived and is most likely associated with moist convective regions deep in Jupiter's atmosphere. The longitudinal periodicity of the lightning storms may represent the effects of a planetary scale atmospheric wave trapped at the depth of the moist convection^11,12.