Photometric observations of 630.0-nm OI and 427.8-nm N2+ emission from South Pole and McMurdo Stations during winter: Analysis of temporal variations spanning minutes to yearly timescales

Time series analysis of wide field-of-view photometer measurements of OI 630.0-nm (originating from a wide O layer in the thermosphere between 200 km and ~300 km and peaking at 250 km) and N2+ 427.8-nm (originating from the mesopause at 95 km) emissions taken simultaneously from South Pole station and from McMurdo (78 S geographic) during winter periods of 2003-2005 are presented. The high sampling rate and extended duration of measurements at both locations allow for the analysis of phenomena with periods spanning order of minutes to seasonal variations. It is shown that 1) 24-, 12-, 8-, and 6-, 4.8-, and 4-hour tidal influences dominate the spectrum from McMurdo at both altitudes and are substantially weaker at South Pole station, 2) higher frequency variations (i.e., with periods of 90-, 24-,15-, 9-, 6-, and 3.3 minute) are occasionally observed which may be related to periodic injection of plasma associated with Pc magnetospheric resonances, and 3) the 630.0-nm emission at South Pole station steadily decreases throughout the winter period, whereas the emission level remains relatively constant at McMurdo, indicating a general reduction in the horizontal transport of plasma poleward of McMurdo. These results lend insight into the role of tides and meridional transport in the high latitude neutral atmosphere as well as to plasma-neutral coupling (e.g., plasma injection) at high geomagnetic latitudes.