[P-EM12] Coupling Processes in the Atmosphere-Ionosphere System

[PEM12-17] Ionospheric Lamb Waves with Conical Phase Fronts Following the 2022 Tonga Eruption Unveiled by Beidou GEO Observations

*Ruoxi Li¹, Jiuhou Lei¹, Shun-Rong Zhang², Huixin Liu³ (1.University of Science and Technology of China, 2.Massachusetts Institute of Technology, 3.Kyushu University)

Prior observational uncertainties have hindered the precise understanding of the link between tropospheric Lamb waves and ionospheric disturbances. In this study, we precisely extracted ionospheric Lamb waves originating from the epicenter of the January 15, 2022 Tonga eruption, propagating upward in a conical structure. This was achieved by using line-of-sight observations from the Beidou geostationary satellites, which eliminated the spatiotemporal ambiguity introduced by the relative motion of GPS satellites, enabling the clear extraction of the Lamb signal in the ionosphere. The observed L1 mode speed (~323 m/s) and period (~30 min) were consistent with those of the tropospheric Lamb wave, suggesting that the ionospheric Lamb wave is likely driven by the surface Lamb wave, leading to a conical wave-front that expands with altitude. This study highlights the significant role of Lamb waves in transmitting energy from epicenters through Earth’s atmosphere and plasma systems.