Lidar Observation of Summer Mesopause Region Diurnal and Semi-diurnal Tides in Temerature, Zonal and Meridional Winds

The Colorado State Two-beam Na Lidar has been configured for simultaneous measurement of the profiles of temperature, zonal and meridional winds in the mesopause region over Fort Collins (41N, 105W). Observations on these dynamical variables covering full diurnal cycles have begun since April 2002. Two campaigns, one between the end of May and the beginning of June and the other between the end of July and the beginning of August were completed, yielding a total of 448 hours of summer data with 12 sets of full 24-hour continuous observation. Harmonic decomposition of these data into 24-, 12-, 8- and 6- hour periods are under way. The results of the diurnal and semi-diurnal tidal amplitudes and phases derived from this thus-far unique data set will be compared to the model output of GSWM00 migrating tidal model in summer months. They will be also compared to the new GSWM model under development, which includes nonmigrating tidal forcing due to latent heat release associated with raindrop formation in deep convective clouds in the tropical troposphere. Science implication on the middle atmosphere dynamics will be discussed in relation to the model-observation comparison.