Thermospheric Exospheric Temperature and Composition Responses on 15 January 2022 Tonga Volcanic Eruption Based on the Ionosonde Observations

Abstract

Abstract We report thermospheric exospheric temperature and composition responses on the 15 January 2022 Tonga volcanic eruption. The temperature and composition profiles are inversed from three ionosonde (MHJ45, EG931, FF051) observed electron density profiles (∼150–200 km) using our new method (Li, Ren, et al., 2023, https://doi.org/10.1029/2022ja030988). The retrieved exospheric temperatures all showed obvious eruption‐induced perturbations, with maximum disturbance magnitude of ∼200 K at MHJ45 and ∼100 K at EG931 and FF051. The temperature variations were related to eruption‐excited thermospheric waves and their propagation with different speeds. While column ∑O/N2 had no evident changes similar to temperatures, which were basically consistent with GOLD observations. In comparison, higher thermospheric O/N2 has larger eruption‐related changes, maybe due to the exponential increase of thermospheric wave amplitudes with height. The application of our inversion method, combined with continuous observations and global coverage of ionosonde data, provide a possibility to further investigate thermospheric responses to different geophysical conditions.

Keywords

• exospheric temperature
• neutral composition
• ionosonde observations
• thermospheric inversion
• GOLD