Summary
During the period 1993–96, transmissions from the US Navy Navigational Satellite System (NNSS) polar orbiting satellites, received at Casey station (66.28°S, 110.5°E geographic) in Antarctica, were used to investigate the amplitude scintillations at 150 MHz and the Total Electron Content (TEC) obtained from the differential phase technique. Investigations of ionospheric polar patches, and polar holes were carried out. The phase and amplitude data were recorded using a JMR-1 satellite receiver system, with all measurements logged on a PC. In order to locate the patches and polar holes, the TEC data were mapped in magnetic local time (MLT) versus invariant latitude (L) magnetic coordinates. Patches were observed in the polar cap region, at various locations and times during the April–August period of the years 1994 and 1995. The polar hole, a feature of the 0000–0300 MLT region at 75° to 80°L, was also observed at various times through the winter months. Average monthly TEC values were calculated, and compared to those obtained from the Parameterised Ionospheric Model (PIM) version 1.4, Daniell et al. (1995).