Abstract:

Auroral images taken by all sky camera are one of important data sources for studying dynamic processes in the polar regions related with magnetospheric substorm, particle precipitation and upper atmospheric properties. It is also essential for understanding solar wind magnetosphere ionosphere coupling. In this paper we use a correlation analysis technique of moving random pattern to calculate the shift velocity of auroral image. Thus the obtained velocity is a kind of “bulk” or “average” velocity of whole image, instead of the velocity for some certain points or parts in the auroral pattern. The technique is used to analyze an example of aurora australis recorded at Zhongshang Station in the Antarctica on June 23, 1997. The results show that the maximal velocity of the auroral pattern in this event is 2.8km/s in east-west direction. Since it takes only a few seconds for energetic particles to travel from the magnetotail to the ionosphere, the obtained aurora velocities would directly reflect the shift situation of the auroral particle source region in the magnetotail.