Tides observed by Na lidar at Colorado State University and studies of anomalous winter diurnal tide using TIMED/SABER and HAMMONIA

The Na lidar at Colorado State University (40°N, 105°W) has the capability to measure mesopause region (80-110 km) temperature, zonal and meridional winds over full diurnal cycles. By performing harmonic analysis on this unique data set from May 2002 to April 2006, monthly climatologies of diurnal and semidiurnal tidal perturbations have been obtained. Since solar thermal tides are global scale waves, global tidal signatures deduced from satellite observations will greatly extend the spatial coverage beyond that of a single ground-based station. Therefore, results of satellite observations and GCM predictions are expected to provide global perspectives and deeper understanding of tidal behavior deduced from local observations. In this paper, tidal perturbations observed by the CSU Na lidar are compared with reconstructed tides observed by the TIMED/SABER instrument and with HAMMONIA model outputs to elucidate the global context of the nearly-evanescent temperature diurnal tides observed by the CSU Na lidar during the winter solstice period. This anomalous behavior is studied, along with information provided by observations from the TIMED/SABER instrument and HAMMONIA model, to ascertain the possible influence of nonmigrating tides on CSU Na lidar observations during this period.