First observations of ionospheric irregularities and flows over the south geomagnetic pole from the Super Dual Auroral Radar Network (SuperDARN) HF radar at McMurdo Station, Antarctica

Abstract

[1] Observations from the first 100 days of operation of the Super Dual Auroral Radar Network (SuperDARN) radar at McMurdo Station, Antarctica are presented. The observations are examined for incidence of ionospheric scatter, which is higher than has been found at the auroral zone radars of the SuperDARN network. During some hours of each day, the probability of observing ionospheric scatter exceeded 90%. In the later portion of the period examined, there was a period of time each day during which the scatter incidence dropped significantly. Incidence was as examined versus solar illumination of the ionosphere, and it was found that the decreases coincided with periods when the ionosphere was in darkness. From this, it is concluded that propagation effects were the reason for the decreases. Plasma velocity observations from the period are also presented and compared with the prevailing interplanetary magnetic field (IMF). The observations were averaged over the central polar cap (Λ > 85°) and were selected for intervals when the radar line of sight was nearly parallel to the Earth-Sun (E-S) line or perpendicular (E-S-perp) to it. A linear relationship was found between the IMF z component and the E-S velocity and similar relationship between the E-S-perp velocity and the IMF y component. There was a significant spread of velocities about the best fit lines. The IMF and average velocity time series were cross-correlated for a number of intervals, and it was found that the average correlation was about 50%, though during some intervals, the correlation exceeds 80%. No explanation is given for the variance of the correlation.