Aeronomy: The Relationship Between Mass, Luminosity and Radar Scattering Cross-section for Small-mass Meteors and their Effects on the Mesosphere

航空学：小质量流星的质量、光度和雷达散射截面之间的关系及其对中间层的影响

• 批准号: 1523097
• 负责人: Robert Michell
• 金额: $ 23.9万
• 依托单位: University of Maryland, College Park
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-04-01 至 2020-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1523097&HistoricalAwards=false
• 关键词: Aeronomy; Relationship; Between; Mass; Luminosity

The scientific objective of the study is to estimate the input of meteoric material into Earth's upper atmosphere, which is an important process that affects the ionosphere, thermosphere, mesosphere and atmosphere. Determining the meteoric mass distribution is critical for characterizing the mass input into the mesosphere -- including the metal deposition -- which plays a significant role in the local chemical processes. The meteoric mass is then transported to the middle atmosphere, where coupling with the lower atmosphere occurs. The current models for predicting the speed at which this transport occurs are sensitive to small changes in the total flux of mass from meteors -- which is largely unknown over the observable mass range. The PIs approach of using both optical and radar techniques simultaneously will enable an effective cross-calibration of the two techniques for calculating meteor mass, resulting in a significantly more accurate estimate of the total meteor mass input. In this study, simultaneous optical and radar observations of meteor head echoes are proposed to set constraints on luminosity and ionization efficiencies, respectively, in order to determine meteoroid mass in the 100 microgram to 100 milligram range. Current data sets of common-volume radar and optical observations of meteors from several different radars are be used to address the science goals. Additional campaigns are proposed at specific radar sites, in order to improve and enhance the meteoroid mass and flux estimates based on lessons learned and the limitations of the current data. The main result expected is the production of mass distribution indexes of meteors from the sporadic meteor complex. The use of multiple radars will allow different regions of the sky -- both Southern and Northern -- to be covered and enable the detection of a large range of masses due to the varying sensitivities of the radars. There is a lack of knowledge in several important areas in this whole process and the proposed research will be a valuable tool in solving several issues, such as the formation of noctilucent and polar stratospheric clouds and the presence of meteoric dust. As a result of the review process and careful consideration, this proposal is funded for a period of three years.

这项研究的科学目标是估计进入地球高层大气的流星物质，这是影响电离层、热层、中间层和大气层的一个重要过程。确定流星质量分布对于确定进入中间层的质量输入-包括金属沉积-的特征至关重要，而金属沉积在当地化学过程中发挥着重要作用。流星质量然后被输送到中层大气，在那里与低层大气发生耦合。目前预测这种传输速度的模型对流星总质量通量的微小变化很敏感----在可观测的质量范围内，这在很大程度上是未知的。同时使用光学和雷达技术的PI方法将能够有效地交叉校准用于计算流星质量的两种技术，从而大大提高对流星总质量输入的估计。在这项研究中，建议同时对流星头回波进行光学和雷达观测，分别对光度和电离效率设定限制，以便确定100微克至100毫克范围内的流星体质量。目前的数据集的共同体积雷达和光学观测流星从几个不同的雷达被用来解决的科学目标。建议在特定的雷达站点开展更多的活动，以便根据所吸取的经验教训和现有数据的局限性，改进和提高流星体质量和通量的估计。预期的主要结果是从零星流星群中产生流星的质量分布指数。使用多个雷达将使天空的不同区域-南部和北方-得到覆盖，并由于雷达的灵敏度不同而能够探测大范围的质量。在这一整个过程中，对几个重要领域缺乏了解，拟议的研究将是解决几个问题的宝贵工具，如南极和极地平流层云的形成以及流星尘埃的存在。经过审查和认真审议，这项建议获得了为期三年的资金。