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Jupiter’s atmospheric jet streams extend thousands of kilometres deep
Nature ( IF 64.8 ) Pub Date : 2018-03-08 , DOI: 10.1038/nature25793
Y. Kaspi , E. Galanti , W. B. Hubbard , D. J. Stevenson , S. J. Bolton , L. Iess , T. Guillot , J. Bloxham , J. E. P. Connerney , H. Cao , D. Durante , W. M. Folkner , R. Helled , A. P. Ingersoll , S. M. Levin , J. I. Lunine , Y. Miguel , B. Militzer , M. Parisi , S. M. Wahl

The depth to which Jupiter’s observed east–west jet streams extend has been a long-standing question. Resolving this puzzle has been a primary goal for the Juno spacecraft, which has been in orbit around the gas giant since July 2016. Juno’s gravitational measurements have revealed that Jupiter’s gravitational field is north–south asymmetric, which is a signature of the planet’s atmospheric and interior flows. Here we report that the measured odd gravitational harmonics J3, J5, J7 and J9 indicate that the observed jet streams, as they appear at the cloud level, extend down to depths of thousands of kilometres beneath the cloud level, probably to the region of magnetic dissipation at a depth of about 3,000 kilometres. By inverting the measured gravity values into a wind field, we calculate the most likely vertical profile of the deep atmospheric and interior flow, and the latitudinal dependence of its depth. Furthermore, the even gravity harmonics J8 and J10 resulting from this flow profile also match the measurements, when taking into account the contribution of the interior structure. These results indicate that the mass of the dynamical atmosphere is about one per cent of Jupiter’s total mass.

中文翻译:

木星的大气喷射流延伸数千公里深

木星观测到的东西向急流延伸的深度是一个长期存在的问题。解决这个难题一直是朱诺号航天器的主要目标,自 2016 年 7 月以来,它一直在环绕这颗气态巨行星的轨道上运行。 朱诺号的引力测量表明,木星的引力场是南北不对称的,这是这颗行星大气和内部流动。在这里,我们报告测量到的奇重力谐波 J3、J5、J7 和 J9 表明观测到的急流,当它们出现在云层时,向下延伸到云层以下数千公里的深处,可能是磁区。在约 3,000 公里的深度消散。通过将测得的重力值反演为风场,我们计算了最可能的深层大气和内部流动的垂直剖面,以及其深度的纬度依赖性。此外,当考虑到内部结构的贡献时,由该流动剖面产生的偶数重力谐波 J8 和 J10 也与测量结果相匹配。这些结果表明动力大气的质量大约是木星总质量的百分之一。
更新日期:2018-03-08
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