标题： 预测土星上层大气的声学特征 显示英文标题

标题： Predicting the Acoustic Signatures of Saturn's Upper Atmosphere

摘要： 针对土星大气中声衰减系数和相速度随频率和高度变化的预测结果进行了介绍和讨论。 研究中考虑的压力范围是1毫巴到1巴，在无风且无云的条件下。 大气成分由主要组分表示，即氢（包括其两种自旋异构体，正氢$_2$和仲氢$_2$）和氦。 H$_2$ 和 He 的浓度假设不随高度变化；然而，考虑了非均匀的正氢和仲氢$_2$ 分布。 通过在一种线性化流体力学模型中引入粘性、热和内部分子弛豫效应来获得声学波数。 环境输入是三个组分（正氢$_2$，仲氢$_2$，He）混合物的比热、剪切粘度和热导率系数的垂直分布，这些数据是在每个压力-温度对下提取的。 作者感谢NASA-Ames创新基金（CIF）提供的资金支持。 显示英文摘要

摘要： Predictions for the acoustic attenuation coefficient and phase speed as functions of frequency and altitude in Saturn's atmosphere are presented and discussed. The pressure range considered in the study is 1 mbar to 1 bar, in windless and cloudless conditions. The atmospheric composition is represented by the major constituents, namely hydrogen (with its two spin isomers, ortho-H$_2$ and para-H$_2$) and helium. The H$_2$ and He concentrations are assumed constant with respect to altitude; however, non-uniform ortho- and para-H$_2$ profiles are considered. The acoustic wavenumber is obtained by incorporating a viscous, thermal, and internal molecular relaxation effects in a linearized fluid dynamics model. The ambient inputs are vertical profiles of the specific heats, shear viscosity, and thermal conductivity coefficients of the three-component (oH$_2$, pH$_2$, He) mixture, extracted at each pressure-temperature pair. The authors acknowledge funding from NASA-Ames Center for Innovation Fund (CIF).