Abstract:

In this paper, using 175 days of aurora observation by all sky imager at 2001, 2002 and 2003 year at Zhongshan station, statistics study show that the occurrence of the multiple arcs and relationships to the geomagnetic activity Kp index. The results show that the occurrence of postnoon multiple arcs demonstrates a single peak distribution, and the maximum peak is at 1445 UT (1645 MLT) and the position lies to the nightside part of “1500 MLT hot spot”(1300—1700 MLT). When Kp index falls between 2 and 3, the occurrence of multiple arcs shows the highest. And spectra of multiple arcs intensity variation have a higher correlation and the similar power spectra character with geomagnetic Pc5 pulsation, which shows that postnoon Pc5 pulsation maybe be associated to the occurrence of the multiple arcs.