Comparative Planetary Aeronomy: Venus and Titan Upper Atmosphere Energetics, Structure and Dynamics

比较行星航空学：金星和土卫六高层大气能量、结构和动力学

• 批准号: 0406650
• 负责人: Stephen Bougher
• 金额: --
• 依托单位: Regents of the University of Michigan - Ann Arbor
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-07-01 至 2007-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0406650&HistoricalAwards=false
• 关键词: Comparative; Planetary; Aeronomy; Venus; Titan

AST 0406650BougherIn this project directed by Dr. Stephen Bougher, the thermosphere and ionosphere of Titan will be examined in great detail,making use of in-situ and remote observations provided by the Cassini Orbiter. In preparation for these observations, fundamental progress can be made in understanding the thermal, compositional and dynamical processes at work in the Titan upper atmosphere by making use of multi-dimensional thermospheric models. The present research effort is devoted to the development, testing, running, and processing of outputs from a detailed3-D thermospheric general circulation model (TGCM) for Titan's upper atmosphere. This Titan TGCM will incorporate a self-consistent treatment of energetics, dynamics, composition, plus external forcings (from the Sun and Saturn's magnetosphere). The objectives for developing this Titan TGCM are to: (1) construct a 3-D model framework sufficient to capture the feedbacks that link the temperature, composition, and wind structures of the Titan upper atmosphere above 600-700 km, (2) generate a prediction tool that can be used later for Cassini Mission thermosphere-ionosphere data analysis, (3) compare Titan thermospheric energetic and dynamical processes with those of other non-magnetic planets (especially Venus), and (4) provide diagnostic interpretation of the underlying processes giving rise to the Titan thermospheric features simulated. In particular, both solar extreme ultraviolet-ultraviolet (EUV-UV) and Saturn magnetospheric forcing (ionization and neutral heating) will be incorporated into the Titan TGCM and the thermospheric responses examined over the solar cycle, Titan seasons, and Titan's orbital position within Saturn's magnetosphere. An expanded understanding of the feedbacks of these Titan thermospheric processes will be achieved as detailed comparisons are made with similar processes in the Venus upper atmosphere. The addition of this new Titan TGCM (with its combined solar plus magnetospheric forcing) will complement the existing Titan TGCM, and provide extended capability. This research activity will make a significant advance in the characterization of the Titan upper atmosphere itself, as well as providing another thermospheric environment for detailed comparison to the structure and dynamics of the Venus, Earth, and Mars thermosheres. The team assembled on this project has many years of experience developing and running TGCM models as well as constructing the detailed inputs that are required to drive the energetics and dynamics of these planetary upper atmospheres. Prior TGCM simulations for Venus, Earth, and Mars have been used extensively in comparative studies, forecasting campaigns, and spacecraft and ground-based data analysis activities. For the proposed Titan and Venus TGCM studies, the research tasks are distributed across senior personnel and a graduate student at the University of Michigan. This approach broadens the impact of the present research by training new planetary scientists for the future. Finally, the results from this research will be disseminated through planned publications as well as the distribution of archival TGCM products through an existing public website at the University ofMichigan. In this manner, the exploration and understanding of our solar system will beadvanced.***

AST 0406650Bougher 在这个由 Stephen Bougher 博士指导的项目中，将利用卡西尼轨道飞行器提供的现场和远程观测来详细检查土卫六的热层和电离层。在为这些观测做准备的过程中，通过利用多维热层模型，可以在理解土卫六高层大气中的热、成分和动力学过程方面取得根本性进展。目前的研究工作致力于开发、测试、运行和处理土卫六高层大气的详细三维热层大气环流模型 (TGCM) 的输出。这个泰坦 TGCM 将结合对能量学、动力学、成分以及外部强迫（来自太阳和土星磁层）的自洽处理。开发泰坦 TGCM 的目标是：(1) 构建一个足以捕获 600-700 公里以上泰坦高层大气的温度、成分和风结构的反馈的 3-D 模型框架，(2) 生成一个预测工具，稍后可用于卡西尼任务热层-电离层数据分析，(3) 将泰坦热层能量和动力学过程与其他非磁性过程进行比较 行星（特别是金星），以及（4）提供了对产生模拟泰坦热层特征的潜在过程的诊断解释。特别是，太阳极紫外-紫外线（EUV-UV）和土星磁层强迫（电离和中性加热）都将被纳入泰坦 TGCM 中，并检查太阳周期、泰坦季节和土星磁层内泰坦轨道位置的热层响应。通过与金星高层大气中的类似过程进行详细比较，将对这些土卫六热层过程的反馈有更深入的了解。新增的泰坦 TGCM（结合太阳能和磁层强迫）将补充现有的泰坦 TGCM，并提供扩展的功能。这项研究活动将在泰坦高层大气本身的表征方面取得重大进展，并提供另一个热层环境，以便与金星、地球和火星热层的结构和动力学进行详细比较。该项目组建的团队在开发和运行 TGCM 模型以及构建驱动这些行星高层大气的能量和动力学所需的详细输入方面拥有多年的经验。先前对金星、地球和火星的 TGCM 模拟已广泛用于比较研究、预测活动以及航天器和地面数据分析活动。对于拟议的泰坦和金星 TGCM 研究，研究任务分配给密歇根大学的高级人员和一名研究生。这种方法通过为未来培训新的行星科学家来扩大当前研究的影响。最后，这项研究的结果将通过计划的出版物以及通过密歇根大学现有的公共网站分发 TGCM 档案产品进行传播。通过这种方式，我们对太阳系的探索和理解将会得到推进。***