Motions in Jovian Hot Spot–Plume Regions Using Voyager Images

Abstract

We have measured the motions and wind velocity vectors in six jovian hot spot–plume areas (latitudes 0° to +12°) using high resolution Voyager 1 and 2 images separated by one jovian rotation (∼10 hr). Rapid changes in cloud forms take place in a few hours at scales from 100 to 2000 km. No large scale organized motions, e.g., diagonal convergence along the plume tails toward hot spots or circulation patterns, such as those recently reported using Galileo images separated by 1 hr, have been found. We show that particle evaporation and cloud element mixing in the upper ammonia cloud could be fast enough to dissipate the small cloud elements, such as those used as tracers by the Galileo SSI team, in less than 10 hr.