Twenty-four-hour observations of aurora at the southern auroral zone

The west-to-east nighttime reversal in longitudinal auroral motions is observed at Byrd, Antarctica, as at other auroral zone stations. Because of the high geographic latitude of the station, it is possible to see the aurora throughout the day, and a second reversal in longitudinal motion is observed. This reversal, from eastward to westward motion, tends to occur approximately 10 hours later than the nighttime reversal. The morphology of the ‘day-time’ aurora is described here; it differs in several ways from that of the aurora commonly observed in the hours near local midnight at this and other auroral zone stations.