摘要
作为地球空间环境的重要组成部分,地磁场和电离层是地球物理研究中的重要方向.新的观测数据和处理方法为人们更加深入地认识地磁场和电离层时空变化之间的相互作用发挥了巨大的促进作用.本文利用欧洲轨道测定中心(CODE)提供的全球电离层垂直总离子浓度地图(GIM)数据和Swarm卫星的观测数据,基于数据统计的方法,对太阳平静期不同纬度地区地磁场和电离层时空变化之间的相互作用进行了分析.从地磁场对电离层时空变化的作用来看,本文利用Swarm卫星数据发现电离层电子浓度在赤道地区呈"马鞍"形分布,在高纬度地区变化剧烈,验证了因地磁场对电离层时空变化影响导致的电离层赤道异常和极盖吸收等现象的存在,同时利用GIM数据通过张量秩-2分解和主成分析发现沿地磁场方向电离层的空间变化更加迅速,体现出地磁场对电离层时空变化的约束作用.从电离层对地磁场时空变化的作用来看,基于CHAOS-5模型对地磁内源场和磁层环电流磁场的预测,本文从Swarm卫星磁测数据中分离出电离层中电流体系的磁效应,其中包括赤道电集流、中纬度地区的Sq电流体系和极区电集流的磁效应,为进一步反演电离层电流体系奠定了基础.
As important components of the geospace environment,the geomagnetic field and ionosphere are significant topics in geophysical research.New observation data and advanced data processing methods can promote the understanding of the interactions between the spatio-temporal variations of the geomagnetic field and ionosphere.Based on the Global Ionospheric Map(GIM)data provided by the Center for Orbit Determination in Europe(CODE)and the data provided by the Swarm satellite constellation mission,the interactions between the spatio-temporal variations of the geomagnetic field and ionosphere are analyzed during solar quiet periods using statistical methods.For the effects of geomagnetic field on the spatio-temporal variations of the ionosphere,we have found that the ionospheric electron content has a saddle-shaped distribution in the equatorial region and dramatic changes at high latitudes based on the Swarm data.Such phenomena verify the existence of equatorial anomalies and polar cap absorption in the ionosphere caused by the geomagnetic field.Meanwhile,based on GIM data,we have found that the ionosphere changes rapidly in the direction of the main geomagnetic field using tensor rank-2 decomposition and principal component analysis.This phenomenon shows the constraints of the geomagnetic field on the spatio-temporal variations in the ionosphere.For the effects of the ionosphere on the spatio-temporal variations of the geomagnetic field,CHAOS-5 model is employed to predict the geomagnetic inner field and magnetic field created by magnetospheric ring currents.Based on the CHAOS-5 model prediction,the magnetic field caused by the currents in the ionosphere is separated from the Swarm data.Those currents include the Equatorial Electrojets(EEJ),Sq current system in mid-latitudes and Polar Electrojets(PEJ).Our investigation lays the foundation for inversion of the ionospheric current system from those magnetic effect.
作者
卢世坤
李义红
李夕海
刘代志
LU Shi-kun;LI Yi-hong;LI Xi-hai;LIU Dai-zhi(Rocket Force University of Engineering,Xi’an 710025,China;Tsinghua University,Beijing 100084,China)
出处
《地球物理学进展》
CSCD
北大核心
2019年第2期454-461,共8页
Progress in Geophysics
基金
国家自然科学基金(41774156)资助
关键词
地磁场
电离层
时空变化
太阳平静期
Geomagnetic field
Ionosphere
Spatio-temporal variations
Solar quiet periods
