Statistical Analysis of Gravity Waves in the Mesopause Region Based on OI 557.7 nm Airglow Observation Over Mohe, China

This study statistically investigates gravity wave (GW) characteristics in the mesosphere over Mohe, China (53.5°N, 122.3°E), and utilizes three years of all-sky airglow imager data (2019–2021). A total of 2397 GW events and 608 ripple events were determined by OI airglow images on 262 clear nights. The statistical results indicate that the observed GW phase speeds ranged from 0 to 100 m/s, periods from 10 to 50 min, and horizontal wavelengths from 55 to 85 km. Notably, the observed periods and horizontal wavelengths in the Mohe region are significantly longer than in other same-latitude regions. In addition, the observed GWs showed a strong tendency to propagate northward in the first three seasons, while they shifted southeastward in winter. Specifically, northeastward propagation dominates in spring and summer, while northwestward propagation with a minor southeastward component prevailed in autumn. Based on the European Center for Medium-Range Weather Forecasts Reanalysis and the Specified Dynamics Whole Atmosphere Community Climate Model with thermosphere and ionosphere eXtension (SD-WACCM-X), further investigation suggests that tropospheric convection is the dominant source of the GWs in summer and autumn, and the generation of GWs is primarily driven by the jet stream systems in spring. In winter, GW may be affected by localized sources and filtering by the upper atmospheric background wind. This study provides valuable references for the GW parameterization in general circulation models in the northern China region.