Figure 1. Map of Antarctica showing the stations used in this paper. South Pole (SPO, -75.5 Inv), Mawson (MAW, -70.5 Inv), Syowa (SYW, -66 Inv) and Halley (HAL, -61.6 Inv). Also marked are the magnetic south pole (MSP) and the auroral oval for Q=4 (Akasofu and Holzworth, 1978) conditions at 12UT.