Dayside Auroral Characteristics as Observed from Svalbard

Abstract

Observations of dayside aurora from Svalbard recorded by multichannel meridian scanning photometers and all-sky video cameras from four days in December 1988 are presented along with magnetometer data from the Svalbard-North Norway chain of stations. These examples indicate that the midday aurora over Svalbard can be separated in different latitudinal regions, possibly as signatures of the magnetic cusp and cleft. The cusp auroral signature is characterized by stable 630.0nm emissions and weak 557.7nm emissions, although transient discrete forms may occur in this region. Within the more extended cleft, discrete auroral structures are more common. Video camera observations reveal eastward drift of 4km/s in one of these sporadic events, associated with a magnetic disturbance propagating at the same speed. The activity level of long period (several minutes) irregular magnetic pulsations increases as the dayside aurora approaches the zenith or during intensity enhancements.