Gravity Wave Parameters and Their Seasonal Variations Study near 120°E China Based on Na LIDAR Observations.

Based on the established LIDAR chain along the 120 degrees E meridian in China, the gravity wave (GW) activity between 80 and 105 km and the seasonal behavior of temporal and spatial spectra at Beijing, Hefei and Hainan were studied with three years of continued observations. The averaged GW-induced atmospheric density perturbations are near 6%, which in summer are obviously larger than in winter. The semiannual maxima occur near the solstice and the minimum emerges around the equinox at different latitudes. Besides, as a disparity, the density perturbation of GW is still active considerably in winter at low latitude at Hainan. The spectra of vertical wave number Fa(m) and observed frequency Fa(omega) show power law shapes, of which the average is near -3 and -1.7, respectively, and both spectra with special values all exhibit similar seasonal behavior as the atmospheric density perturbations shows. This behavior is explained by multiple effects possibly originating from Tibet plateau (TP) and the main GW source in China was roughly calculated by the LIDAR observation method for the first time located at the TP boundary.