OBSERVATIONAL EVIDENCE OF TIDAL GRAVITY-WAVE INTERACTIONS USING THE UWO-2-MHZ RADAR

The degree of interaction between atmospheric gravity waves and tides is an issue which is of great importance in middle atmosphere studies. It is especially important with regard to tidal variability which is frequently observed in the mesosphere and lower thermosphere, but as y et has not been subject to adequate study. In this paper, we present s ome strong observational evidence of such interactions made with the U WO 2 MHz radar near London, Canada. Our observations show significant correlation between gravity waves and tides (diurnal) at certain times of the year, and the nature of the correlation is intermittent and va ries with time of year. It is possible that differences between tidal amplitudes at sites with mesoscale separations may be explained in ter ms of such phenomena. We also propose a simple model which is found to be consistent with the major features of the observed data.