Estimation of Thermospheric Oxygen Density and Temperature From Combined Optical and Radar Measurements

通过结合光学和雷达测量来估计热层氧密度和温度

• 批准号: 0626013
• 负责人: Gary Swenson
• 金额: --
• 依托单位: University of Illinois at Urbana-Champaign
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-08-01 至 2011-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0626013&HistoricalAwards=false
• 关键词: Estimation; Thermospheric; Oxygen; Density; Temperature

Neutral atomic oxygen, O, is a key species in Earth's upper atmosphere, where it dominates thermospheric composition between ~200-700 km. Knowledge of its density, [O], is required for spacecraft operations in low earth orbit, for understanding the coupling between the thermosphere and ionosphere, and for characterizing the dynamic atmospheric response to drivers such as space weather or climate change. This project is to develop a new technique for [O] estimation based on Incoherent Scatter Radar (ISR) data and coincident optical emission observations. The new technique will provide both O density and temperature estimates over the altitude range 550-850 km. It bases the [O] estimation on O and H+ rather than O and O+ coupling, thereby avoiding the difficulties associated with uncertainties in the O+-O collisional cross section that have plagued traditional ground-based techniques in the past. This is made possible by new incoherent scatter multi-ion fitting techniques recently developed at Arecibo for the topside ionosphere. The technique will be applied to nearly 20 years of optical and radar data available from the Arecibo observatory to compile a climatology of mid-latitude [O] and temperature variations for the thermosphere. New measurements facilitating improvements in optical detector sensitivity and dual-beam radar capability at Arecibo will be used to extend the altitude range of the neutral density inversions down to lower altitudes. This will allow for an independent, much improved estimation of the so-called "Burnside factor", F, a measure of the discrepancy between theoretical and empirical estimates for the O+-O collision frequency. The large discrepancies in existing estimates of this factor constitute a long-standing puzzle in thermosphere chemistry. Broader impacts of this project include the usefulness of this new technique for a wide range of other atmospheric studies. In addition, the project includes research opportunities for students and would help further the independent research career of a young, successful female scientist.

中性原子氧，O，是地球上层大气中的关键物种，它在约200-700 km之间主导了热圈组成。在低地球轨道上的航天器操作所必需的知识，以了解热层和电离层之间的耦合，并表征对驾驶员（例如太空天气或气候变化）的动态大气反应。该项目是为了基于不一致的散射雷达（ISR）数据和一致的光学发射观测来开发一种新技术，以进行[O]估计。新技术将在高度范围550-850 km上提供O密度和温度估计值。它基于O和H+而不是O和O+耦合的[O]估计，从而避免了O+ -O碰撞横截面中与过去困扰着传统地面技术的不确定性相关的困难。最近在Arecibo开发的顶部电离层开发的新的不连贯的散射多离子拟合技术使这成为可能。该技术将应用于近20年的光学和雷达数据，可从Arecibo天文台提供，以编译中纬度的气候[O]和热圈的温度变化。新的测量值促进了Arecibo的光学检测器灵敏度和双光束雷达能力的改善，以扩展中性密度反转的高度范围至较低的高度。这将允许对所谓的“伯德因子”（F）进行独立的，大大改进的估计，这是O+-O碰撞频率的理论和经验估计之间差异的度量。现有估计值的巨大差异构成了热层化学中的长期难题。该项目的更广泛的影响包括这种新技术对其他大气研究的有用性。此外，该项目还为学生提供研究机会，并将有助于进一步的年轻，成功的女科学家的独立研究职业。