Investigation of irregularities in the southern high latitude ionosphere

During the period 1993-1996, transmissions from the US Navy Navigational Satellite System (NNSS) polar orbiting satellites, received at Casey (66.28 degrees S, 110.5 degrees E) in Antarctica, were used to investigate the amplitude scintillations on 150 MHz and the Total Electron Content (TEC) obtained from the differential phase technique. Investigations of the ionospheric polar patches, and polar holes were carried out. The phase and amplitude data was 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 MLT magnetic coordinates. Patches were observed in the polar cap region, at various locations and times during the April-August period of 1994 and 1995. The polar hole, a feature of the 0-3 MLT region at -75 to -80 degrees Invariant Latitude, was also observed at various times through the winter months. Average monthly TEC values were calculated, and compared to those obtained from the Parametrized Ionospheric Model, PIM. (C) 2001 COSPAR. Published by Elsevier Science Ltd. All rights reserved.