暴时密度增强区附近电离层不均匀体研究

基于IGS提供的TEC数据, 研究了2003年10月大磁暴期间的暴时密度增强(Storm Enhanced Density, SED)现象; 利用GPS观测数据, 计算出ROTI (Standard deviations of ROT)指数, 分析了SED边界附近电离层小尺度不均匀体结构的时间和空间演变. 研究表明, 在磁暴主相期间SED边界附近不均匀体随着磁暴的发展逐渐增多; 在主相的中后期不均匀体的分布密集度达到最大; 在恢复相期间, 不均匀体分布很少; 随着磁暴的发展, 不均匀体开始主要集中在40~45oN范围内, 随后向高纬漂移, 主要集中在45~55oN范围内. 

Study of Ionospheric Irregularities in the Vicinity of SED Region During a Super Geomagnetic Storm

Small-scale ionospheric irregularities can cause strong amplitude and phase scintillations of radio wave signals passing through the ionosphere. In this paper, the phenomena of Storm Enhanced Density (SED) were studied during a super geomagnetic storm in October 2003 by using the TEC data of IGS. Rate of TEC Index (ROTI) is calculated with the observed data of GPS. The ROTI has been used to analyze the spatial and temporal distribution of small scale ionospheric irregularities in the vicinity of SED region. It shows that the irregularities near the SED border were gradually increased with the development of geomagnetic storm during the main phase, and the distribution density reached its maximum value in the latter part of the main phase, and then was reduced during the recovery phase. Initially, the irregularities were mainly distributed in latitudes 40o~45oN. Subsequently, the irregularities drifted to higher latitude, and were mainly distributed in latitudes 45 o~55oN. This study provides an important theoretical foundation on revealing the propagation characteristics of radio waves passing through the vicinity of SED region.