Collaborative Research: CEDAR--Tomographic Array for Lightning and Ionospheric Studies (TALIS)

为了充分了解闪电对电离层密度结构的影响，该项目将在高频(1-30兆赫)部署共置电离层和闪电射频阵列，用于D区和E区成像，并部署甚低频(0-500千赫)和甚高频(120-150兆赫)雷达进行闪电研究。观测计划将通过电离层数据同化四维(IDA4D)模式的计算得到扩充。该模型将利用获得的观测结果以及其他机会主义的E区数据来源，尤其是来自洛斯阿拉莫斯便携式脉冲器和Cibola飞行实验卫星的数据来源，对从E区到上方的高度进行层析重建。这些活动的目标是阐明对流层和电离层之间的耦合过程，特别是闪电和E区电离增强之间的相互作用，即所谓的零星E。目前的想法表明，将能量从对流层传输到低电离层的主要机制有两种：第一种是机械波活动，第二种是与闪电相关的电效应，包括电磁脉冲和相对论电子。波的机械耦合可以在传播到F区之前增加零星-E层的峰值等离子体密度。来自闪电的放电通过电磁耦合，并可能通过从在这些高度发现的陨石金属原子的周围群体中产生更长寿命的金属离子来增加等离子体的峰值密度。然而，尽管对瞬变发光事件(TLE)的观测表明雷暴与中高层大气之间确实发生了相互作用，但人们对闪电和电离层之间的电磁耦合知之甚少。目标是在回答以下电离层/对流层耦合问题方面取得重大进展：(1)闪电发射和零星E层发展之间的耦合机制是什么？(2)闪电发射和电离层电导变化之间的关系是什么？(3)我们可以在多大程度上利用闪电发射的Rf值和电离层的特征来同时模拟和分析闪电发射的物理特征和电离层响应的详细结构？

In order to fully characterize the effect of lightning on ionospheric density structures, this project will deploy co-located ionosphere and lightning RF arrays at HF (1-30 MHz) for D- and E-region imaging, and VLF (0-500 kHz) and VHF (120-150 MHz) radars for lightning studies. The observational program will be augmented by computations from the Ionospheric Data Assimilation Four-Dimensional (IDA4D) model. The model will perform tomographic reconstruction of the ionosphere for heights extending from the E region to above using the observations obtained as well as other opportunistic E region data sources, most notably from the Los Alamos Portable Pulser (LAPP) with the Cibola Flight Experiment (CFE) satellite. The goal of these activities is to elucidate coupling processes between the troposphere and ionosphere, in particular the interaction between lightning and E region ionization enhancements known as sporadic-E. Current thinking suggests that there are two primary mechanisms that transport energy from the troposphere to the lower ionosphere: the first is mechanical wave activity and the second is electrical effects associated with lightning, including electromagnetic pulses and relativistic electrons. The mechanical coupling of waves may increase the peak plasma densities of sporadic-E layers before propagating into the F-region. Discharges from lightning couple electromagnetically and may increase the peak plasma densities by creating more long-lived metal ions from the ambient population of meteoric metal atoms found at these altitudes. However, very little is known about the electromagnetic coupling between lightning and the ionosphere, even though observations of Transient Luminous Events (TLE) indicate that interactions between thunderstorms and the middle and upper atmospheres do occur. The goal is to make significant progress in answering the following questions on ionosphere/troposphere coupling: (1) What is the coupling mechanism between lightning emissions and the development of sporadic E layers? (2) What is the relationship between lightning emissions and the variations of conductances in the ionosphere? (3) To what degree can we use measured RF values of the lightning emissions and characterization of the ionosphere to simultaneously model and analyze the physical characteristics of lightning emissions and the detailed structuring of the ionospheric response?