基于多卫星组网观测的赤道电集流时空变化特征研究

The equatorial electrojet (EEJ), which is caused by Cowling conductivity, represents a ribbon of intense electric current flowing along the dip-equator. It would lead to changes of geomagnetic. The spatio-temporal characterization of EEJ reveals the dynamic/electrodynamic process of ionosphere and the solar wind-magnetosphere-ionosphere coupling. Because of the complexity of physical process of ionosphere and insufficiency of observational data, the result of theoretical model is still not consistent with current observational data. The dominant factor of disturbances of the EEJ along with the changes of the longitude, latitude, local time and season is still not clear. This project, by using the analysis of typical event and statistical analysis, will apply the joint observation of CHAMP, SWARM, Low Earth Orbit satellites "Pearl project", and geomagnetic stations to systemically study the global spatio-temporal characterization of the EEJ . The dependence of the EEJ on the latitude, local time, and season, and the response to solar wind disturbance/ magnetic disturbance would be tried to work out. The implementation of the project will help to reveal the control factors of the change in the EEJ, and deep our understanding of the ionospheric dynamo process and the solar wind-magnetosphere-ionosphere coupling, and provide important reference information for Iono Correction.

赤道电集流（EEJ）是由Cowling电导率通道引起的磁赤道附近的集束状电流，并产生与之对应的地磁变化。赤道电集流的时空变化体现了电离层内部的动力学/电动力学过程以及太阳风-磁层-电离层耦合过程。由于电离层区域物理过程的复杂性和观测不足等原因，理论模型计算与地面实际观测结果有较大差异，赤道电集流经纬度、地方时、季节变化的控制因素以及对太阳风/磁层扰动的响应还不清楚。本项目拟利用CHAMP、SWARM、“珍珠计划”等低轨道卫星以及地面地磁台站的联合观测，通过个例、统计及理论对比分析，系统研究赤道电集流的全球空间分布特征和时间演化规律，弄清赤道电集流对经纬度、地方时、季节的依赖性，分析赤道电集流对太阳风/磁层扰动的响应。项目的实施将有助于揭示赤道电集流变化的控制因素，加深对磁赤道附近电离层发电机过程以及太阳风-磁层-电离层耦合过程的理解，为电离层改正提供重要的参考信息。

赤道电集流（EEJ）是由Cowling电导率通道引起的磁赤道附近的集束状电流，并产生与之对应的地磁变化。赤道电集流的时空变化体现了电离层内部的动力学/电动力学过程以及太阳风-磁层-电离层耦合过程。由于电离层区域物理过程的复杂性和观测不足等原因，理论模型计算与地面实际观测结果有较大差异，赤道电集流经纬度、地方时、季节变化的控制因素以及对太阳风/磁层扰动的响应还不清楚。本项目基于“珍珠计划”低倾角卫星，结合SWARM卫星的相关研究，通过个例、统计及理论对比分析，研究了赤道电集流的时空分布特征，EEJ电流密度分布呈现明显的南北不对称性，峰值电流密度偏离磁赤道向北约1.5°，产生偏移的原因可能是受季节影响或者经度影响。赤道电集流的磁效应影响电离层发电机电流太阳静日变化（Sq）的南北不对称性，并影响地磁场建模的精度以及数据反演的准确度。多卫星同步观测可以有效提高EEJ反演精度，对于研究EEJ小尺度结构有重要意义。研究结果有助于揭示赤道电集流变化的控制因素，加深对磁赤道附近电离层发电机过程以及太阳风-磁层-电离层耦合过程的理解。