基于正则化方法的三维电离层电子浓度重构技术研究

电离层电子浓度的变化显著地影响无线电波的传播，本项目综合利用测高仪、非相干散射雷达、GNSS接收机（地基和空基）以及GNSS掩星试验的电离层观测资料，以国际参考电离层模式（IRI）为背景模式，基于正则化方法（其通过正则化参数来平衡背景信息和观测信息之间的权重）来快速获取准确的中低纬地区的三维电离层电子浓度分布。主要的研究内容包括IRI顶部模式的评估和修正、Tikhonov正则化和全变差正则化算法及其混合正则化方案的建立、结合模型函数方法的单正则化参数和多正则化参数的最优选择，以及定量分析不同类型观测资料对电离层电子浓度重构结果的贡献。在此基础上研究电离层电子浓度的变化规律，重点分析中低纬电离层大尺度波三和波四结构的时空分布和传播机理以及赤道和低纬电离层Rayleigh-Taylor不稳定性的分布特征。

The ionospheric electron density variation can significantly affect the propagation of the radio waves. This work comprehensively uses the measurements from ionosondes, incoherent scatter radars, GNSS receivers (ground and space-based) and GNSS radio occultation experiments, and sets the International Reference Ionosphere (IRI) as the background model, to derive the accurate three-dimensional ionospheric electron density in the middle and low latitude based on the regularization method. The main contents are the evaluation and correction of the IRI topside model, establishment of the Tikhonov regularization algorithm, total variation regularization algorithm and hybrid regularization algorithm, selection of the single and multiple regularization parameters, and quantitative analysis of the contributions to the reconstruction results from different type of measurements. On the basis of the above, we can study the variation of the ionospheric electron density in detail, and mainly focus on the spatial/temporal distribution and propagation characteristic of the ionospheric large-scale wave structures (wavenumber 3 and wavenumber 4) in the middle and low latitude and the variation of the Rayleigh-Taylor instability in the equatorial and low-latitude ionosphere.