Observation of moist convection in Jupiter's atmosphere

The energy source driving Jupiter's active meteorology is not understood(1) . There are two main candidates: a poorly understood internal heat source a nd sunlight. Here we report observations of an active storm system possessi ng both lightning and condensation of water. The storm has a vertical exten t of at least 50 km and a length of about 4,000 km. Previous observations(2 ,3) of lightning on Jupiter have revealed both its frequency of occurrence and its spatial distribution, but they did not permit analysis of the detai led cloud structure and its dynamics. The present observations reveal the s torm (on the day side of the planet) at the same location and within just a few hours of a lightning detection (on the night side). We estimate that t he total vertical transport of heat by storms like the one observed here is of the same order as the planet's internal heat source. We therefore concl ude that moist convection-similar to large clusters of thunderstorm cells o n the Earth-is a dominant factor in converting heat flow into kinetic energ y in the jovian atmosphere.