This study examines the impact of increased CO₂ on the migrating diurnal tide (DW1), which is generated by solar absorption and latent heating. Using WACCM-X under the RCP 8.5 scenario, we find a +1 %/decade trend in DW1 amplitude at 20–70 km and a −2 %/decade trend at 90–110 km. The increase is likely due to reduced density and stronger convection near the equator, while the decrease may result from enhanced eddy diffusion in the mesosphere that suppresses tidal growth.

This study analyzes changes in the ionospheric response to solar flux over five complete solar cycles (1957 to 2023). We use Juliusruh hourly data of the peak electron density of the F2 layer, NmF2, and three solar extreme ultraviolet (EUV) radiation proxies. The response is better represented by a cubic regression, and F30 shows the highest correlation for describing NmF2 dependence over time. These results reveal a decrease in NmF2 influenced by the intensity of the solar activity index.

Investigation of winds is important to understand atmospheric dynamics. In the summer mesosphere and lower thermosphere, there are three main wind flows: the mesospheric westward, the mesopause southward (equatorward), and the lower-thermospheric eastward wind. Combining almost 2 decades of measurements from different radars, we study the trend, their interannual oscillations, and the effects of the geomagnetic activity over these wind maxima.

The geomagnetic and solar effect on Es is studied. The negative correlation between Es and geomagnetic activity at mid-latitude is related to the decreased meteor rate during storm period. The increased Es occurrence in high latitude relates to the changing electric field. The positive correlation between Es and solar activity at high latitude is due to the enhanced IMF in solar maximum. The negative correlation in mid and low latitudes relates to the decreased meteor rate during solar activity.

Little is known about the climate change of wind systems in the mesosphere and lower thermosphere at the edge of space at altitudes from 70–110 km. Meteor radars represent a well-accepted remote sensing technique to measure winds at these altitudes. Here we present a state-of-the-art climatological interhemispheric comparison using continuous and long-lasting observations from worldwide distributed meteor radars from the Arctic to the Antarctic and sophisticated general circulation models.