Yadav Rakesh Kumar, Heimpel Moritz, Bloxham Jeremy
Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA 02138, USA.
Department of Physics, University of Alberta, T6G 2J1 Edmonton, Canada.
Sci Adv. 2020 Nov 13;6(46). doi: 10.1126/sciadv.abb9298. Print 2020 Nov.
The surfaces of Jupiter and Saturn have magnificent vortical storms that help shape the dynamic nature of their atmospheres. Land- and space-based observational campaigns have established several properties of these vortices, with some being similar between the two planets, while others are different. Shallow-water hydrodynamics, where the vortices are treated as shallow weather-layer phenomenon, is commonly evoked for explaining their formation and properties. Here, we report novel formation mechanisms for vortices where the primary driving mechanism is the deep planetary convection occurring in these planets. Using three-dimensional simulations of turbulent convection in rotating spherical shells, we propose two ideas: (i) Rotating turbulent convection generates deep axially aligned cyclones and anticyclones; (ii) a deep planetary dynamo acts to promote additional anticyclones, some as large as Jupiter's Great Red Spot, in an overlying atmospheric layer. We use these ideas to interpret several observational properties of vortices on Jupiter and Saturn.
木星和土星的表面有壮观的涡旋风暴，这些风暴有助于塑造它们大气的动态特性。基于地面和太空的观测活动已经确定了这些涡旋的几个特性，其中一些在两颗行星之间是相似的，而另一些则不同。浅水流体动力学将涡旋视为浅层天气层现象，通常用于解释它们的形成和特性。在这里，我们报告了涡旋的新形成机制，其主要驱动机制是这些行星中发生的深层行星对流。通过对旋转球壳中湍流对流的三维模拟，我们提出了两个观点：（i）旋转湍流对流产生深层轴向排列的气旋和反气旋；（ii）深层行星发电机作用于在上覆大气层中促进额外的反气旋，其中一些反气旋与木星的大红斑一样大。我们用这些观点来解释木星和土星上涡旋的几个观测特性。
