Earth Planets Space, Vol. 57 (No. 5), pp. 393-398, 2005
Guangxin Zhao1,2,3, Libo Liu1, Baiqi Ning1, Weixing Wan1, and Jiangang Xiong1
1Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029, China
2Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, China
3Graduate School of the Chinese Academy of Sciences, China
(Received August 25, 2004; Revised April 18, 2005; Accepted April 18, 2005)
Winds measured by an all-sky meteor radar have been used to investigate the terdiurnal tide in the mesosphere and lower thermosphere (MLT) region over Wuhan (30.6°N, 114.4°E). We present a climatology of the terdiurnal tide at low-mid latitude site during the period of April 2002 to December 2004. The terdiurnal peak is distinct in the long-term power spectrum of the wind. The monthly and seasonal mean maximum amplitudes have values of 7 m/s and 5 m/s, respectively. The short-term amplitudes can occasionally reach up to 30 m/s, and at times the terdiurnal tide is as large as the diurnal and semidiurnal ones. It seems that the meridional component is more regular than the zonal one. An obvious annual variation is observed in the meridional phases with a phase leading in winter than that in summer. The annual variation for the terdiurnal tidal amplitude is not obvious, and is variable from year to year in our observations. This seasonal trend is slightly different from earlier studies at other locations.
Key words: Meteor radar, terdiurnal tide, mesospheric dynamics, nonlinear interaction.