LARGE-SCALE WAVES IN THE UPPER-MESOSPHERE AT ANTARCTIC HIGH-LATITUDES

Upper-mesosphere combined optical measurements of wind and temperature fields at Amundsen-Scott Station (South Pole) and wind radar measurements at Scott Base (78-degrees-S, 167-degrees-E) show the presence of large-scale waves in this region of the atmosphere. At Amundsen-Scott the largest amplitude wave observed with sub-diurnal periodicity appears with a frequency near 2.4/day (approximately 10.1 hour period), with a westward phase progression of wavenumber one. The presence of a wave with this periodicity is confirmed by the observations at Scott Base. The combination of the experimentally-found period, phase progression, associated small-temperature oscillations, and theoretical considerations lead to the interpretation of this wave as a Lamb wave. The present combination of spatially-resolved optical measurements and radar measurements illustrates the value of multiple-station and multiple-technique observations in elucidating the upper-mesosphere dynamical state, as well as the properties of the waves propagating through the medium where the observations are being made.