Phyus.org March 3, 2023
The effects of volcanic eruptions on the ionosphere have been well studied, however, evidence for the anticipated upper atmospheric neutral variations and their exact extents of change are rarely available. An international team of researchers (China, Germany, USA – MIT) found dramatic thermospheric disturbances following the 15 January 2022 Tonga eruption. The GRACE-FO and Swarm-C observations from the accelerometers exhibited three successive thermospheric density waves at ∼500 km altitudes propagating concentrically across the globe at 200–450 m/s phase speed and two of the three waves converged at the antipode of the epicenter. A large-scale and long-lasting neutral density depletion within a radius of approximately 10,000 km around the epicenter occurred, along with the density enhancement around the antipode of the epicenter. Such an enhancement is comparable in the relative intensity with respect to the no-eruption condition, to the effect of a moderate geomagnetic storm. According to the researchers their study offers observational evidence of substantial global upper thermospheric perturbations well above their origin near the Earth’s surface due to a volcanic eruption…read more. Open Access TECHNICAL ARTICLEÂ
Thermospheric densities at 510 km (in units of 10−12 kg/m3) along GRACE-FO trajectories during the eruption of the Tonga volcano… Credit: Geophysical Research Letters, Volume 50, Issue 3 e2022GL102265