Modeling the Altitude Distribution of Meteor Head Echoes Observed with HPLA Radars: Implications for the Radar Detectability of Meteoroid Populations
Modeling the Altitude Distribution of Meteor Head Echoes Observed with HPLA Radars: Implications for the Radar Detectability of Meteoroid Populations
复制标题
对 HPLA 雷达观测到的流星头回波的高度分布进行建模：对流星体群雷达可探测性的影响
DOI：
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发表时间：
2019
影响因子：
5.3
通讯作者：
D. Nesvorný
中科院分区：
文献类型：
--
作者：
N. Swarnalingam;D. Janches;J. Carrillo;P. Pokorny;J. Plane;Z. Sternovsky;D. Nesvorný
雷达探测到的流星高度分布对仪器的响应函数很敏感，因此可以深入了解雷达测量中涉及的物理过程。反过来，这可以用来确定流星体的烧蚀和电离速率，以及最终地球上的输入通量。在这项工作中，我们通过考虑主要彗星族来源的流星体数量，对三个高功率和大孔径雷达系统的雷达流星头回波高度分布进行建模。在这个模拟中，我们首先使用小型流星体撞击地球高层大气的动力学模型的结果来模拟传入的质量、速度和进入角分布。然后，我们将这些与化学烧蚀模型相结合，并建立流星体电离率作为质量、速度和进入角的函数，以确定这些雷达应检测到产生的流星的高度以及这些雷达检测到的每个流星群中产生的流星的部分。我们探讨了不同尺寸的头部等离子体以及头部回波方面灵敏度对雷达散射的可能影响。我们发现建模的高度分布通常与测量结果非常一致，特别是对于超高频雷达。此外，我们的结果表明，符合观测结果所需的木星族彗星（JFC）粒子数量低于天文模型的预测。目前尚不清楚这种差异是由于动力学模型对 JFC 流星体的过度预测，还是由于在流星体穿过地球大气层时处理烧蚀、电离和检测过程中未考虑的物理过程。
The altitude distribution of meteors detected by a radar is sensitive to the instrument’s response function and can thus provide insight into the physical processes involved in radar measurements. This, in turn, can be used to determine the rate of ablation and ionization of the meteoroids and ultimately the input flux on Earth. In this work, we model the radar meteor head echo altitude distribution for three High Power and Large Aperture radar systems, by considering meteoroid populations from the main cometary family sources. In this simulation, we first use the results of a dynamical model of small meteoroids impacting Earth’s upper atmosphere to model the incoming mass, velocity, and entry angular distributions. We then combine these with the Chemical Ablation Model and establish the meteoroid ionization rates as a function of mass, velocity, and entry angle in order to determine the altitude at which these radars should detect the produced meteors and the portion of produced meteors from each population that are detected by these radars. We explore different sizes of head plasma as well as the possible effects on radar scattering of the head echo aspect sensitivity. We find that the modeled altitude distributions are generally in good agreement with measurements, particularly for ultra-high-frequency radars. In addition, our results indicate that the number of particles from Jupiter Family Comets (JFCs) required to fit the observations is lower than predicted by astronomical models. It is not clear yet if this discrepancy is due to the overprediction of JFC meteoroids by dynamical models or due to unaccounted physical processes in the treatment of ablation, ionization, and detections of meteoroids as they pass through Earth’s atmosphere.
流星烧蚀的化学模型
影响因子：
6.3
作者：
Vondrak T
通讯作者：
Vondrak T