Jupiter’s Red Oval BA: Dynamics, Color, and Relationship to Jovian Climate Change

Abstract

Jupiter now has a second red spot, the Oval BA. The first red spot, the Great Red Spot (GRS), is at least 180 yr old. The Oval BA formed in 2000 was originally white, but part turned red in 2005. Unlike the Great Red Spot, the red color of the Oval BA is confined to an annulus. The Oval’s horizontal velocity and shape and the elevation of the haze layer above it were unchanged between 2000 and 2006. These observations, coupled with Jupiter’s rapid rotation and stratification, are shown to imply that the Oval BA’s 3D properties, such as its vertical thickness, were also unchanged. Therefore, neither a change in size nor velocity caused the Oval BA to turn partially red. An atmospheric warming can account for both the timing of the color change of the Oval BA as well as the persistent confinement of its red color to an annulus.