An isolated baroclinic eddy as a laboratory analogue of the Great Red Spot on Jupiter

Abstract

We have recently presented evidence1 supporting the hypothesis2 that the long-lived large oval atmospheric eddies on Jupiter and Saturn, including Jupiter's anticyclonic Great Red Spot (GRS) and White Ovals and the cyclonic ‘barges’, are manifestations of ‘slantwise’ or ‘sloping’ convection in a rotating fluid, implying that they are involved in the horizontal transport of heat towards or away from the edges of the atmospheric zones or belts in which they occur, and that their kinetic energy derives directly from the action of gravity on the density field associated with horizontal gradients of temperature. These eddies would then be dynamically similar to the highly stable closed ‘baroclinic’ eddies produced in certain laboratory experiments on thermal convection in a rotating fluid subject to internal heating or cooling1,3. We now present laboratory findings that bear on the interpretation of the isolated nature of the GRS, including the crucial demonstration that a single intense stable baroclinic disturbance that is strongly localized in azimuth can form readily when the impressed conditions are close to the transition from axisymmetric to non-axisymmetric flow.