Modelling and Observation of Sporadic E Layers and their dependence on upper atmospheric dynamics

关于电离层不规则的空间和时间变化的知识可用于提高通信和导航系统的可靠性，也可用于对高层大气耦合过程的科学调查。在拟议的研究项目中，将根据卫星观测和模型计算，更详细地研究较低电离层零星E层的形成及其全球分布。该项目的主要目标是分析全球零星E分布与高层大气动力学、地球磁场和较低E区电离率之间的关系。CHAMP、GRACE和FORMOSAT-3/COSMIC卫星的GPS无线电掩星数据将被用来得出零星E的全球分布。这些分布将与全球卫星对热层风场和地球磁场的测量相关联。此外，还将开发和应用一个数值模式，以研究全球范围内零星E的形成，并解释观测到的零星E的全球分布。来自流星雷达测量的低电离层电离率被用作模型的一个重要输入参数。开发的模型将在案例研究中得到验证和应用，以调查在解释所观测到的零星E发生的年度周期、其时空分布及其与地球磁场的相关性方面存在的悬而未决的问题。

Knowledge on spatial and temporal variations of ionospheric irregularities can be used to increase the reliability of communication and navigation systems, but also for scientific investigations of coupling processes in the upper atmosphere. Within the proposed research project the formation of lower ionospheric sporadic E layers and their global distribution will be investigated in more detail based on satellite observations and model calculations. The main objective of this project is to analyse the global sporadic E distribution with respect to upper atmospheric dynamics, the Earth’s magnetic field and lower E region ionisation rates. GPS radio occultation data from the satellites CHAMP, GRACE and FORMOSAT- 3/COSMIC will be used to derive global distributions of sporadic E. These distributions will be correlated with global satellite based measurements of the thermospheric wind field and the Earth’s magnetic field. In addition a numerical model will be developed and applied to investigate the formation of sporadic E on a global scale and to interpret the observed global distributions of sporadic E. Ionisation rates in the lower ionosphere from meteor radar measurements are used as an important input parameter of the modelling. The developed model will be validated and applied within case studies to investigate open questions in the interpretation of the observed annual cycle of sporadic E occurrence, its spatial and temporal distribution and its correlation with the Earth’s magnetic field.