海南地区强磁暴期间强区域扩展F事件研究

利用2004年海南DPS-4数字测高仪观测到的强区域扩展F(SSF)数据,分析研究了5个强磁暴(Dst＜-100 nT)事件期间海南SSF的响应特征.结果发现,在海南地区,5个强磁暴事件中有3个磁暴Dst最小值位于2200-0200 LT之间,在磁暴主相及恢复相初期均出现了SSF现象,这种触发作用可能源于磁层直接渗透电场的作用,而另两个磁暴Dst最小值均发生在白天,一个SSF现象出现在磁暴的恢复相晚间,另一个SSF现象出现在超强磁暴的初相晚间,后者可能由该超强磁暴的急始造成的直接渗透电场所触发;5个强磁暴期间发生的SSF现象或者仅出现在午夜前,或者先出现在午夜前并持续到午夜后;同时,还就这些观测结果与Dabas等人有关磁暴对ESF影响的结论进行对比和讨论. 

Strong Range Spread-F Characteristics Observed in Hainan During Intense Storm

The response of equatorial ionosphere during geomagnetic storms is one of the important issues related to space weather studies and how they affect the occurrence characteristics of equatorial spread-F is one of the prominent research fields. In this study, the Strong range Spread-F （SSF） data from DPS-4 digisonde during the five strong storms （Dst 〈 -100nT） period in 2004 in Hainan （19.4°N, 109.1°E, MLat. 9.0°N） China are used to investigate the effects of geomagnetic storms on SSF. The results show that there are three storms, the minimum Dst of which lied in the period 2200-0200 LT and SSF occurred during the main or earlier recovery phase of these storms, the role of directly penetrated electric field of magnetosphere maybe the only important factor for occurrence of SSF. The other two storms whose minimum Dst lied in the dayside also trigger SSF during the night of recovery phase of one storm and initial phase of another super intense storm. The SSC of the later super storm led to penetrated electric field towards to lower latitude/equator of ionosphere which triggered SSF. During the storms, SSF occurred only before midnight or started midnight and continued after midnight. The comparisons between the results of Dabas et al. and ours also discussed.