WHAT CAN BE LEARNED FROM ROTATIONAL TEMPERATURES DERIVED FROM GROUND-BASED AIRGLOW OBSERVATIONS ABOUT THE AERONOMY OF THE SOUTHERN-HEMISPHERE

Ground-based measurements of rotational temperatures from the O-2 atmospheric and OH bands provide information about the dynamics of the upper atmosphere that is not easily accessible by other means. The spatial density of measuring stations of any kind, capable of determining temperatures in the 80 - 100 km altitude range, is quite low in the entire southern hemisphere, making airglow data the more important. This situation is likely to prevail in the future. In Argentina, our tilting filter spectrometer has been in operation during a number of campaigns since 1984, giving temperatures of OH(6-2) at 86km and of O-2(0-1) at 95km with high temporal resolution (1.5 min). These data, taken at low mid-latitudes (32 degrees S), show strong variations at all time scales, from gravity waves to the tidal and planetary wave range, the annual variation and up to the long-term variation of the mean state related to the solar cycle. An overview of the results obtained, so far, is presented. For a complete analysis of the large-scale variations, the horizontal spacing of measuring stations is likely to remain grossly insufficient, unless supplemented by satellite measurements, or data from other additional sources, for which specially designed international campaigns would be needed.