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

电离层和等离子体层覆盖约60 km高度的高度，直到赤道平面上约3-5个地球半径处的等离子体层顶，其变化非常复杂且强耦合。电离层等离子体层耦合过程的调查基本上有助于了解观测到的电离层和等离子体层的变化下，定期和扰动的条件。最近，一些GNSS无线电掩星任务，例如，CHAMP、COSMIC和Fengyun-3C为高空间分辨率的电离层-等离子体层变化和空间天气研究提供了反演电离层和等离子体层总电子含量和电子密度的独特机会。为了充分利用这些任务的潜力，我们建议实施新的方法，其中包括一个新的映射函数的几何变换的观测数据，接收机偏差和相位中心变化（PCV）估计的低地球轨道（LEO）卫星。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-等离子体层电子含量和垂直电子密度分布的TEC估计将用于研究电离层的气候特征和电离层-等离子体层关系，确定和研究一些特定的电子密度分布形状，如高纬度的E层主导电离层（ELDI）。此外，电离层异常的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）可能是由强电离层等离子体磁耦合的研究。因此，除了考虑[O]/[N2]等主要中性粒子的热层组成比外，研究还包括垂直等离子体漂移和中性风和电场等相关动力，德国航天中心和上海天文台之间拟议的联合项目可为国际空间天气子午圈计划作出实质性贡献，并为电离层等离子体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.