基于武汉和三亚VHF雷达的中低纬E层不均匀体比较研究

Observations of the ionospheric E region irregularity by Wuhan and Sanya VHF coherent scatter demonstrate similarities as well as distinct differences in the radar echoes and spatial-temporal distribution. The similarity and difference indicate that the study of the excitation mechanism and the effects of controlling factors of the irregularities in mid- and low-latitude ionospheric E layer is a scientific question worth in-depth discussion and research. This project is of great significance in enrichment and development of the relative researches on the generation mechanism of the mid- and low-latitude ionospheric irregularities. In this project, VHF coherent scatter observations of the irregularities in the ionospheric E region in Wuhan and Sanya will be utilized, combined with other radio, optical and satellite detection and measurement techniques, in order to thoroughly and comprehensively compare and investigate the temporal and spatial evolution and the physical mechanism of the ionospheric E region irregularities in Wuhan and Sanya. The controlling factors, statistical characteristics and core mechanism of mid- and low-latitude ionospheric E region irregularities will be revealed in this project. Meanwhile, some other relative problems concerning the E region irregularities will be investigated in this project, including the responsive characteristics of mid- and low-latitude E region irregularities in China to the space weather events, the electromagnetic coupling mechanism of the mid- and low-latitude E region and F region mid-scale disturbance as well as the response of E region irregularities to the physical processes in various MLT regions.

武汉和三亚VHF相干散射雷达结果显示两个地区的E层不均匀体的雷达回波形态和时空分布，既存在类似之处，也存在明显的差异，反映了中低纬E层不均匀体的激发机制和控制因素的影响，是一个值得深入探讨和研究的科学问题，这一课题的研究对于丰富和发展中低纬度电离层不均匀体生成物理机制的研究具有十分重要的意义。本项目利用武汉和三亚的VHF相干散射雷达的电离层E层不均匀体观测，并结合位于武汉和三亚的其他无线电、光学以及卫星探测手段，深入全面地比较研究武汉和三亚E层不均匀体的时空分布演化规律及物理过程，从而辨识和明析中纬和低纬度电离层E层不均匀体激发的控制参数、统计规律、核心机制，并探讨我国中低纬度E层不均匀体对空间天气事件响应特征，中低纬度E层和F层中尺度扰动的电磁耦合机制、E层不均匀体对MLT区域物理过程的响应等。

中低纬度电离层不均匀体是电离层中各种复杂物理过程的重要体现，各种宏观的物理量，例如电子密度、风场、电场、背景地磁场、大气波动等，在激发电离层不均匀体过程都发挥了重要的作用，而由这些宏观物理量偏离平衡态导致各种等离子体不稳定性是产生自然电离层不均匀体的核心物理机制。与被广泛研究的电离层F层不均匀体相比，电离层E层不均匀体的时空分布规律和形成机制都具有明显不同之处，具有纬度和背景依赖特征。本项目利用位于我国中低纬度地区的VHF电离层相干散射雷达、流星雷达、电离层垂测仪和卫星观测数据对中低纬度电离层E层不均匀体进行联合观测，深入全面地研究我国中低纬度E层不均匀体的时空分布演化规律及物理过程，探讨我国中低纬度E层不均匀体对空间天气事件响应特征，中低纬度E层和F层中尺度扰动的电磁耦合机制、E层不均匀体对MLT区域物理过程的响应等。本项目的主要研究成果包括：a）中低纬度突发E层统计特性分析；b）突发E层非风剪切机制的模拟研究；c）武汉电离层E层不均匀体回波形态特征事例研究和统计分析；d）磁平静期曲靖地区白天F层不均匀体的特例分析；e）中低纬度电离层E层不均匀体的数值模拟研究；f）中低纬度夜间电离层E-F层耦合过程和半球间耦合过程分析研究；g）中低纬度电离层E层不均匀体干涉测量技术研究；h）中低纬度电离层E层不均匀体雷达多波束扫描探测技术研究；j）中低纬度电离层E层和F层对准6天波动的响应研究。