Ionospheric-plasmaspheric variations and mechanism from multi-satellite space-based GNSS measurements

电离层和等离子层覆盖了大约60km的高度，直到赤道平面上3-5个地球半径处的等离子层顶，它们的变化是非常复杂和强耦合的。电离层-等离子体耦合过程的研究有助于理解在规则和扰动条件下观测到的电离层和等离子体的变化。近年来，CHAMP、COSMIC和风云- 3c等GNSS射电掩星任务为电离层和等离子体层总电子含量（TEC）和电子密度的高空间分辨率研究电离层-等离子体层变化和空间天气提供了独特的机会。为了充分发挥这些任务的潜力，我们建议实施新的方法，其中包括一个新的映射函数，用于观测数据的几何转换，接收器偏差和低地球轨道卫星的相位中心变化（PCV）估计。考虑并减少了多卫星GNSS观测以及高阶电离层传播对电离层和等离子体层参数估计的影响。改进的电离层-等离子层电子含量和垂直电子密度剖面的TEC估计将用于研究电离层和电离层-等离子层关系的气候特征，识别和研究高纬度地区电子层主导电离层（ELDI）等特定电子密度剖面形状。此外，还研究了电离层异常，如威德尔海和鄂霍次克海异常或仲夏夜间异常（MSNA）和夜间冬季异常（NWA），这些异常可能是由电离层-等离子层强耦合引起的。因此，除了考虑[O]/[N2]等主要中性物质的热层组成比外，研究还包括垂直等离子体漂移和相关的中性风和电场等动力。DLR和SHAO的联合项目可以为国际空间气象子午线圈计划（IMCP）做出重要贡献，并为电离层-等离子层物理学的新科学发现提供良好的基础。

The ionosphere and plasmasphere cover the altitude of about 60 km height up to the plasmapause at about 3-5 Earth radii in the equatorial plane, whose variations are very complex and strongly coupled. The investigation of ionosphere-plasmasphere coupling processes contributes essentially to understand the observed ionospheric and plasmaspheric variations under regular and perturbed conditions. Recently, a number of GNSS radio occultation missions, e.g., CHAMP, COSMIC and Fengyun-3C, provide a unique opportunity to retrieve the ionospheric and plasmaspheric total electron content (TEC) and electron density for studies of ionospheric-plasmaspheric variations and space weather with high spatial resolution. In order to fully utilize the potential of these missions we suggest the implementation of new approaches, among them a new mapping function for geometrical transformation of observation data, receiver bias and phase center variation (PCV) estimates of Low Earth Orbit (LEO) satellites. Multi-satellite GNSS observations as well as higher order ionospheric propagation effects on ionospheric and plasmaspheric parameters estimates are considered and reduced. Improved TEC estimates of the topside ionosphere-plasmasphere electron content and vertical electron density profiles will be used to study climatological features of the ionosphere and ionosphere-plasmasphere relationships, identify and study some specific electron density profile shapes like the E-layer dominated ionosphere (ELDI) at high latitudes. Furthermore, ionospheric anomalies as the Weddell sea and Okhotsk sea anomaly or the Mid Summer Nighttime Anomaly (MSNA) and the Nighttime Winter Anomaly (NWA) are studied that might be explained by strong ionosphere-plasmasphere coupling. Thus, besides considering the thermospheric composition ratio of dominating neutrals like [O]/[N2], the investigations include vertical plasma drifts and related dynamic forces such as neutral winds and electric fields.The proposed joint project between DLR and SHAO can essentially contribute to the International space weather Meridian Circle Program (IMCP) and provides an excellent basis for new scientific findings in ionosphere-plasmasphere physics.