The mesosphere and lower thermosphere (MLT) region is strongly modulated by gravity wave (GW) perturbations, and the momentum flux of GW is essential in quantitatively understanding and modeling atmospheric structure at all altitudes. In this study, we present the seasonal variations, long-trend of mesospheric density and GW momentum flux observed by the meteor radars at Davis Station (68.6°S, 77.9°E), in Antarctica, Svalbard (78.3°N, 16°E), Tromsø (69.6°N, 19.2°E) in the Arctic. In general, u’w’ decreases and v’w’ increases as altitude increasing, and westward maximum of u’w’ and northward maximum of v’w’ in spring and autumn at upper altitude. the momentum flux u’w’ and v’w’ is anti-correlated with the background winds (u/v). The seasonal variations in the Davis Station meteor radar relative densities in the southern polar mesopause are mainly dominated by an annual oscillation (AO). The mesopause relative densities observed by the Tromsø meteor radars at high latitudes in the Northern Hemisphere show mainly an AO and a relatively weak semiannual oscillation (SAO).
 

MLT,meteor radar,gravity wave