CEDAR: Investigating Helium Behavior and Its Role in the Thermosphere

CEDAR：研究氦气行为及其在热层中的作用

• 批准号: 1452309
• 负责人: Jeffrey Thayer
• 金额: $ 49.98万
• 依托单位: University of Colorado at Boulder
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-01 至 2020-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1452309&HistoricalAwards=false
• 关键词: CEDAR; Investigating; Helium; Behavior; Its; CEDAR; Investigating; Helium; Behavior; Its

This project addresses fundamental physical processes that govern the behavior of helium throughout the thermosphere and also elucidates its role in understanding the behavior of other thermospheric constituents. The thermosphere is the domain for many low-earth-orbiting satellites and the constituent makeup, their transport properties, and their bulk motion contribute significantly to satellite drag. Helium has been a missing constituent in current thermosphere general circulation models and plays an important role in determining satellite drag effects in the upper thermosphere through its impact on the total mass density. Additionally helium is an excellent dynamical tracer creating the possibility of using helium observations to describe the poorly measured wind systems in the thermosphere. The project addresses ways of understanding complexity in the geospace system and will be carried out as a collaboration between the University of Colorado and NCAR. Two graduate students will be involved in the project. Through this award, the implementation of a scheme to fully describe helium structure in altitude, latitude, longitude, local time, season, solar cycle and geomagnetic activity in NCAR community models will be completed. This new scheme will then be used to evaluate the processes responsible for the distribution and variation of helium. This understanding can then be projected to other gasses whose overall structure and behavior are complex but, by contrasting with helium, can be evaluated for its transport dependencies. The dynamical influences on composition also impact estimates of total mass density, where helium during solar minima can have a direct contribution. This work will lead to a better characterization of the thermosphere and can be used to improve satellite drag studies. Model output will be compared with satellite observations for evaluation.

该项目解决了控制整个热层氦气行为的基本物理过程，还阐明了其在理解其他热层成分的行为中的作用。热层是许多低地球卫星的结构域和组成型的化妆，它们的运输特性以及它们的大量运动对卫星阻力产生了重大贡献。氦在当前热圈一般循环模型中一直是缺失的组成部分，并且通过其对总质量密度的影响来确定上层热层中的卫星阻力效应起着重要作用。另外，氦气是一种出色的动力示踪剂，可以使用氦观测来描述热层中测得的风系统。该项目涉及理解地理空间中复杂性的方法，并将作为科罗拉多大学和NCAR之间的合作进行。两名研究生将参与该项目。 通过该奖项，将完成一项针对NCAR社区模型中高度，纬度，经度，季节，太阳周期和地磁活动的计划充分描述氦结构的计划。然后，该新方案将用于评估负责氦分布和变化的过程。然后可以将这种理解投影到其他总体结构和行为复杂但与氦气相反的气体中，可以评估其运输依赖性。对组成的动力影响也影响了总质量密度的估计值，在太阳能最小值期间的氦气可以直接贡献。这项工作将导致对热圈的更好表征，并可用于改善卫星阻力研究。模型输出将与卫星观测值进行评估。