2004年11月强磁暴期间武汉电离层TEC的响应和振幅闪烁特征的GPS观测

GPS observations of ionospheric effects of the major storm of Nov.7-10,2004

本文利用设在武汉(114.36°E,30.53°N,磁纬19.4°)的GPS电离层TEC和电波闪烁监测仪的测量数据,分析了2004年11月强磁暴期间TEC的响应以及电波闪烁和TEC起伏的特征.结果表明,在这次强磁暴期间,武汉及其邻近地区电离层TEC的响应以正暴相为主,正暴相分别出现在两次主相期间,最大正偏离达到50 TECU.这次磁暴另一个重要影响是主相期间L波段振幅闪烁的活动性及其强度显著增强.S4指数最大接近1.0.伴随增强的闪烁活动,多次观测到深度耗尽的等离子体泡与TEC起伏,TEC变化率的标准差ROTI指数也显著增强.分析揭示,ROTI指数与S4指数呈正相关,相关系数达到0.97.线性回归计算得到,ROTI和S4的比率为9.64.

The TEC and amplitude scintillation measurements of L1 （ 1.575 GHz） signals from GPS satellites have been carried out at Wuhan（ 114.36°E, 30.53°N, magnetic latitude 19.4°） since 2003 using an ionospheric total electron content（TEC） and scintillation monitor to investigate the ionospheric irregularities and TEC disturbances at the region of the equatorial anomaly. In this paper ionospheric effects of the magnetic storm of November, 2004 are analyzed by using GPS observations. Data analysis shows that the ionospheric storm during this magnetic storm mainly exhibits the positive storm phase around Wuhan, and the positive deviations of TECs occur during two main phases of the storm on November 8 and 10 with the largest deviation of 50 TECU. Another primary effect of the storm on the ionosphere is the remarkably enhanced activity and intensity of amplitude scintillations during the later main phase. The maximum value of the S4 index exceeded 1.0. There occurred plasma bubbles and TEC fluctuations initiated from the equatorial region repetitiously at the same time when strong amplitude scintillations occurred. A comparison between amplitude scintillations and TEC fluctuations was made. The statistic analysis shows there is a remarkable positive correlation between standard deviation of the change rate of TEC, the ROTI index, and the S4 index, rhrough a regression analysis it is obtained that the ratio of ROTI to S4 is 9.64.