摘要：We have used high-resolution images obtained with JunoCam onboard the Juno spacecraft during its close flyby of Jupiter on 2017 July 11, to study the dynamics of the Great Red Spot (GRS) at the upper cloud level. We have measured the horizontal velocity and vorticity fields using the clouds as tracers of the flow. We have analyzed a variety of cloud morphologies that serve to characterize different underlying dynamic processes. Long undulating dark gray filaments (2000–10000 km) circulate around the outer part of the vortex moving at high speed (∼120–140 m s−1) where mesoscale waves (wavelength 75 km) indicate stable conditions in this region. At mid distance from the center, a large eddy (radius ∼500 km) is observed in a region of intense horizontal wind shear whereas on the opposite side, compact cloud clusters with cell sizes of ∼50 km, indicative of shallow convection, are observed. The core of the GRS (∼5000 × 3000 km2) is turbulent where the circulation has weakly cyclonic and anticyclonic regions. This variety of phenomena occurs in the upper ammonia cloud layer and haze (thickness ∼20–50 km) that represents the top of a dynamical system with a much deeper circulation.
关键词：planetary systems;planets and satellites: atmospheres
