Midlatitude Neutral Wind Response During the Mother's Day Super-Intense Geomagnetic Storm in 2024 Using Observations From the Chinese Meridian Project

Using new observations from the Chinese Meridian Project (CMP), this study examines the characteristics of neutral winds in the East Asian sector during the Mother's Day super-intense storm in May 2024, primarily focusing on its effects on the disturbances over China and adjacent areas. It is the first time that new measurements from three Dual-Channel Optical Interferometers (DCOIs) are utilized to analyze storm-time neutral winds at an altitude of 250 km in northern China. By developing all northern-hemisphere Super Dual Auroral Radar Network radars including six Chinese Dual Auroral Radar Network (CN-DARN) radars, the newly derived ionospheric convection pattern and its impacts on neutral winds can be well analyzed. The results show that a strong equatorward wind with a maximum amplitude of ∼400 m/s in the meridional component was observed for the first time during the storm main phase. In the East Asian sector, a negative ionospheric storm over China and adjacent areas was accompanied by this enhancement in equatorward wind in the night of May 10. Additionally, ionospheric convection expanded to 43° magnetic latitude (MLAT) with eastward ion velocities exceeding 800 m/s around 50° MLAT. This can strengthen zonal wind in northern China, producing a notable eastward surge of ∼230 m/s measured by new DCOIs in the dawnside sub-auroral region. Wave-like oscillations in neutral winds were observed by multi-DCOI stations, which were associated with the storm-time Traveling Atmospheric Disturbances (TADs). During the storm recovery phase, a high-level total electron content cluster shifted from eastern China to the central regions, which may be attributed to enhanced ∑[O]/[N₂].