Three-dimensional spectral analysis of gravity waves from airglow observations over Northwest China

The three-dimensional spectral analysis method was applied to airglow data from September 2023 to August 2024 derived from an OH airglow imager located at the Hejing station (42.79°N, 83.73°E) to study the propagation characteristics of gravity waves (GWs) over Northwest China. We found that obvious seasonal variations occur in the propagation of GWs. In spring, GWs mainly propagate in the northeast direction. In summer and autumn, GWs mainly propagate in the north direction. However, GWs mainly propagate in the south direction in winter. The direction of GW propagation in the zonal direction is controlled by the wind-filtering effect, whereas the north–south meridional direction is mainly determined by the location of the wave source. We found that the average energy spectrum exhibits a 10%–20% higher intensity in summer and winter compared with spring and autumn. For the first time, we report the seasonal variation characteristics of GWs over the inland areas of Northwest China, which is of great significance for understanding the regional distribution characteristics of GWs.