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arXiv 1608.01434astro-ph.EP
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使用即将到来的朱诺重力测量和动力学逆模型解耦木星的深层和大气流

Decoupling Jupiter's deep and atmospheric flows using the upcoming Juno gravity measurements and a dynamical inverse model

Eli Galanti, Yohai Kaspi

摘要:

对木星上气流的观测基本上只存在于云层,这是由强大的东西向喷流控制的。有人认为这是由于表层薄风化层中的动力学造成的,或者是深层内部圆柱形流动的表现。然而,有可能观测到的风确实是表面风,但存在与之完全分离的深层气流。迄今为止,所有通过诱导密度异常将风与朱诺号测量的重力场联系起来的模型,都只考虑作为观测到的云层风投影的气流。在这里,我们探讨复杂的风动力学的可能性,包括浅天气层风,和一个深流,是从上面的流解耦。上层流是基于观测到的云级流,并设置为衰减与深度。深流的构造是为了产生具有可变宽度和大小的圆柱形结构,从而允许未知深流的各种可能的情况。然后,通过动力学模型将组合流与密度异常和引力矩相关联。伴随逆模型用于优化参数控制设置的深和表面约束流,使这些流可以重建给定的重力场。我们表明,该模型可用于检查各种情况下,包括深流是主导的表面风的情况下。我们广泛地讨论了与模型解决方案的不确定性。伴随方法的灵活性允许广泛的动力学设置,因此当新的观测和物理理解出现时,这些约束可以很容易地实现并用于更好地破译木星流动动力学。

英文摘要:

Observations of the flow on Jupiter exists essentially only for the cloud-level, which is dominated by strong east-west jet-streams. These have been suggested to result from dynamics in a superficial thin weather-layer, or alternatively be a manifestation of deep interior cylindrical flows. However, it is possible that the observed winds are indeed superficial, yet there exists deep flow that is completely decoupled from it. To date, all models linking the wind, via the induced density anomalies, to the gravity field, to be measured by Juno, consider only flow that is a projection of the observed could-level wind. Here we explore the possibility of complex wind dynamics that include both the shallow weather-layer wind, and a deep flow that is decoupled from the flow above it. The upper flow is based on the observed cloud-level flow and is set to decay with depth. The deep flow is constructed to produce cylindrical structures with variable width and magnitude, thus allowing for a wide range of possible scenarios for the unknown deep flow. The combined flow is then related to the density anomalies and gravitational moments via a dynamical model. An adjoint inverse model is used for optimizing the parameters controlling the setup of the deep and surface-bound flows, so that these flows can be reconstructed given a gravity field. We show that the model can be used for examination of various scenarios, including cases in which the deep flow is dominating over the surface wind. We discuss extensively the uncertainties associated with the model solution. The flexibility of the adjoint method allows for a wide range of dynamical setups, so that when new observations and physical understanding will arise, these constraints could be easily implemented and used to better decipher Jupiter flow dynamics.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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