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

本研究的科学目的是估算大气物质对地球上层大气的输入量，这是影响电离层、热层、中间层和大气的重要过程。确定大气质量分布对于表征进入中间层的质量（包括金属沉积）至关重要，这在局部化学过程中起着重要作用。然后，大气物质被输送到中层大气，在那里与低层大气发生耦合。目前用于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。pi同时使用光学和雷达技术的方法将能够有效地交叉校准两种技术来计算流星质量，从而更准确地估计流星的总质量输入。在本研究中，提出了流星头部回波的同时光学和雷达观测，分别设置亮度和电离效率的约束，以确定100微克至100毫克范围内的流星体质量。现有的普通体积雷达数据集和来自几个不同雷达的流星光学观测数据集被用于解决科学目标。建议在特定雷达站开展更多的活动，以便根据吸取的经验教训和现有数据的局限性改进和加强流星体质量和通量的估计。预期的主要结果是从偶发流星复合体中产生流星的质量分布指数。多部雷达的使用将使天空的不同区域——南方和北方——被覆盖，并且由于雷达的不同灵敏度，能够探测到大范围的质量。在整个过程中，有几个重要领域缺乏知识，提出的研究将是解决几个问题的有价值的工具，例如夜光和极地平流层云的形成以及大气尘埃的存在。经过审查过程和仔细审议，为这项建议提供了为期三年的经费。

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.