The Formation and Maintenance of the Zonal Winds of Jupiter and Saturn

木星和土星纬向风的形成和维持

• 批准号: 9423305
• 负责人: Philip Marcus
• 金额: $ 14.5万
• 依托单位: University of California-Berkeley
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-04-01 至 1999-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9423305&HistoricalAwards=false
• 关键词: Formation; Maintenance; Zonal; Winds; Jupiter

94-23305 Marcus Prof. Marcus will model numerically the east-west winds in the upper troposphere (i.e., the visible cloud layer) of Jupiter and Saturn, using 3-D fluid-dynamics. The principal objective is to improve our understanding of why the winds are structured in zones or bands with alternating velocity directions from the equator to the poles. Additionally, the Principal Investigator (PI) will address other unresolved issues of those giant planets' atmospheres -- the number of bands, the magnitude of the wind velocities, the greater velocities of the Saturnian winds compared to the Jovian winds, and the relationship between the winds and the vortices embedded in them. The motivation for the work is that, unlike thermal convection in stars which can be reproduced and studied under laboratory conditions (albeit in simplified form), the mechanism of "east- west" winds of planetary atmospheres has not been modeled in the laboratory and all proposed methods for creating such winds remain mere conjectures. Yet we cannot claim to understand the outer planets until we understand their east-west winds. The PI will base his calculations on two different sets of assumptions: (1) The winds' vertical depth extends over tens of to several hundred density scale heights; and (2) the winds are confined to a thin vertical layer. The point is to decide between the two kinds of theories. The calculations will be done in both spherical and parabolic geometries. The latter geometry has the advantage that a parabolic dish containing a stable fluid overlying a convecting fluid can be built in a laboratory to test the validity of the numerical results, an experiment the PI is suggesting to be carried out by others.

94-23305马库斯教授将使用3-D流体动力学对木星和土星对流层上部(即可见云层)的东西向风进行数值模拟。主要目的是为了提高我们对风的结构的理解，风的结构是从赤道到两极的具有交替速度方向的区域或带。此外，首席调查员(PI)将解决这些巨行星大气的其他悬而未决的问题--频带的数量、风速的大小、与木星风相比土星风的速度更大，以及风和嵌入其中的漩涡之间的关系。这项工作的动机是，与恒星中的热对流不同，恒星中的热对流可以在实验室条件下复制和研究(尽管是以简化的形式)，行星大气中“东-西”风的机制尚未在实验室中建立模型，所有提出的产生这种风的方法仍然只是猜测。然而，在我们了解外行星的东西向风之前，我们不能声称我们了解它们。PI的计算将基于两组不同的假设：(1)风的垂直深度超过数十到数百个密度尺度高度；(2)风被限制在一个很薄的垂直层。关键是要在这两种理论之间做出选择。计算将在球面和抛物面两种几何形状下进行。后一种几何形式的优点是，可以在实验室中建造一个包含稳定流体的抛物面圆盘，以检验数值结果的有效性，PI建议由其他人进行这一实验。