“…Many researchers consider that in the interpretation of the short-time scales atmospheric dynamics (such as gravity waves and tides), the sodium layer can be regarded as a passive tracer (Gardner and Shelton, 1985;Gardner and Voelz, 1987;Kwon et al, 1987;Bills and Gardner, 1993), due to the longer lifetime of sodium atoms above 85 km (Xu and Smith, 2003). Extensive lidar studies of the seasonal variations of the sodium layer were conducted at different latitudes in the 1970s (Gibson and Sandford, 1971;Megie and Blamont, 1977;Simonich et al, 1979;States and Gardner, 1999;Plane et al, 1999;She et al, 2000;Gardner et al, 2005;Yi et al, 2009). With the development of narrowband lidars (Bills et al, 1991;She et al, 1992;Bills and Gardner, 1993;Papen et al, 1995), the mesospheric temperature and wind measurements has complemented sodium observations and helped to us understand the dynamical process in the MLT region.…”