We analysed all-sky camera images observed at Mt. Bohyun observatory (36.2° N, 128.9° E) for the period of 2017–2019. We retrieved gravity wave parameters including horizontal wavelength, phase velocity and period from the image data. The horizontally propagating directions of the wave were biased according to their seasons, exerted with filtering effect by prevailing background winds. We also evaluated the nature of vertical propagation of the wave for each season.

Numerical modelling is used to simulate atmospheric circulation and calculate residual mean meridional circulation (RMC) during sudden stratospheric warming (SSW) events. Calculating the RMC is used to take into account wave effects on the transport of atmospheric quantities and gas species in the meridional plane. The results show that RMC undergoes significant changes at different stages of SSW and contributes to SSW development.

Temperatures obtained from FORMOSAT-3 and COSMIC observations in the stratosphere are analysed for tidal variations. It is seen that non-migrating tides are not very significant in the high-latitude winter stratosphere. It is shown that the observed amplitudes of these tides in earlier studies are most probably a result of aliasing and are not geophysical in nature. Thus, the process of non-linear interactions through which it was believed that they are produced seems to be unimportant.

The aim of this study is to bring local variabilities into a global context. To qualitatively study the impact of global waves on local measurements in winter, we combine local lidar measurements with global MERRA-2 reanalysis data. Our results show that about 98 % of the local day-to-day variability can be explained by the variability of waves with zonal wave numbers 1, 2 and 3. Thus locally measured effects which are not based on global wave variability can be investigated much better.

Interannual variabilities of the zonal mean wind and temperature related to the Rossby wave forcing in the winter stratosphere of the Southern Hemisphere are studied using 38-year reanalysis data. Correlation of the mean fields to the wave forcing is extended to the subtropics of the Northern Hemisphere. This interhemispheric link is caused by the wave forcing which reduces the meridional gradient of the angular momentum and drives the meridional circulation over the Equator in the stratosphere.