Summary
A digital ionosonde (DPS-4) is operated at Casey station, Antarctica, primarily to study the dynamics of the southern polar cap ionosphere. To gain a better understanding of the ionospheric motions involved, animated data displays have been developed using ionospheric drift and ionogram data combined together with together with other geophysical data sets to help identify dynamical features. To delineate ionospheric motions, a sequence of ionosonde measurements, consisting of one drift measurement and one ionogram, is completed at a rate of up to every 2 minutes. Ionospheric changes can then be viewed frame by frame using commercial animation software. This provides a simple means of viewing large amounts of data and identifying, for example, drifting polar patches, or the response of ionospheric drift to changes in the IMF. Since the ionosonde takes measurements throughout the bottomside ionosphere, different height regions (e.g. E and F) can be examined independently or compared directly. Doppler and directional information featured in the animations provides a powerful technique for studying the evolution of ionospheric phenomena such as polar patches. Several campaigns have been run with the DPS-4 during 1997 and early 1998 with the aim of identifying the occurrence and motion of polar patches over Casey. The digisonde data from these periods are examined for correlation with other geophysical data sets such as IMF, Total Electron Content and Scintillation indices (using GPS and NNSS satellites).