Winds in the mesopause region (85–100  km altitude) drive upper-atmospheric dynamics and energy transfer. We present the Asymmetric Spatial Heterodyne Spectrometer, a ground-based instrument, to measure winds by observing the green airglow of atomic oxygen. Lab tests demonstrated the instrument achieves <2 m/s accuracy. Field measurements at a high-latitude site in China showed strong agreement with independent LiDAR data, confirming that the system delivers reliable wind retrievals.

Disruptions of Quasi-Biennial Oscillation modulate the migrating diurnal tide in the mesosphere and lower thermosphere. During the events, wavelengths and phases of the tide remain unchanged, but its amplitude strengthens. The enhancement of water vapor radiative heating, ozone radiative heating and latent heating may contribute to the amplification of the tide amplitude. These features provide insights into the dynamical coupling of troposphere, stratosphere, mesosphere and lower thermosphere.

An equatorial plasma bubble (EPB) event, emerging near dawn and developing after sunrise, was simultaneously observed by an all-sky imager and the global navigation satellite system (GNSS) network. The observed EPBs showed westward drifts, different from post-sunset EPBs. The EPBs occurred in the recovery phase of a geomagnetic storm, possibly playing a key role in initializing their developments. The results provide a new perspective of EPBs, enriching our knowledge of ionospheric irregularity.

The seasonal variations in the mesopause densities, especially with regard to its global structure, are still unclear. In this study, we report the climatology of the mesopause density estimated using multiyear observations from nine meteor radars from Arctic to Antarctic latitudes. The results reveal a significant AO and SAO in mesopause density, an asymmetry between the two polar regions and evidence of intraseasonal oscillations (ISOs), perhaps associated with the ISOs of the troposphere.

Two traveling ionospheric disturbances (TIDs) were observed by the GPS network in Asia following the large meteorite blast over Chelyabinsk, Russia. No TIDs propagating in a global range were found. Features of TIDs were compared with those excited by early nuclear explosion tests. It is inferred from our analysis that the energy release of the Chelyabinsk meteorite blast may not be large enough to excite such ionospheric disturbances in a global range as some nuclear explosions have done.