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) 是地球高层大气中的一个关键物种，它在约 200-700 公里之间的热层组成中占主导地位。了解其密度 [O] 是航天器在近地轨道运行、了解热层和电离层之间的耦合以及表征大气对空间天气或气候变化等驱动因素的动态响应的必要条件。该项目旨在开发一种基于非相干散射雷达 (ISR) 数据和同步光发射观测的 [O] 估算新技术。新技术将提供 550-850 公里海拔范围内的 O 密度和温度估计。它将 [O] 估计基于 O 和 H+，而不是 O 和 O+ 耦合，从而避免了过去困扰传统地面技术的与 O+-O 碰撞截面的不确定性相关的困难。这是通过阿雷西博最近开发的用于上部电离层的新型非相干散射多离子拟合技术实现的。该技术将应用于阿雷西博天文台近 20 年的光学和雷达数据，以编制中纬度 [O] 和热层温度变化的气候学数据。有助于提高阿雷西博光学探测器灵敏度和双波束雷达能力的新测量将用于将中性密度反演的高度范围扩展到更低的高度。这将允许对所谓的“燃烧系数”F 进行独立的、大大改进的估计，F 是 O+-O 碰撞频率的理论估计和经验估计之间差异的度量。现有对该因素的估计存在巨大差异，构成了热层化学中长期存在的难题。该项目的更广泛影响包括这项新技术对于广泛的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，并将有助于进一步推动年轻、成功的女科学家的独立研究生涯。