A team led by Prof. LEI Jiuhou from University of Science and Technology of China (USTC) and collaborators has revealed the notable evidence of the dramatic thermospheric disturbances and global upper thermospheric perturbations of Tonga eruption (15 January, 2022). The study also confirmed that the impact of volcanic eruption has outreached the ionosphere and creeps into the thermospheric density up to 500 km satellite orbiting altitudes.

This eruption significantly redistributed the global neutral density 500 km above the ground, with higher density in the antipode hemisphere and lower density in the volcanic eruption hemisphere.

Researchers further discovered that the Tonga volcanic eruption stimulated thermosphere atmospheric fluctuations with multiple wave modes in the speed range of 200-450 m/s. Thermosphere atmospheric fluctuations propagate globally in concentric circles centered on the Tonga volcano, and some wave models can propagate and converge to the antipode of the volcano, and further diverge from the antipode to continue propagation.

Furthermore, researchers believed that in accordance with the characteristics of propagation, thermosphere atmospheric fluctuations may be related to the upward transmission of energy from gravitational waves, Lamb waves and tsunami waves in the lower atmosphere.

This study initiates to provide the direct effect of the volcanic eruption on thermospheric density, which may expand the understanding of the interactions between the Earth's spheres from the lithosphere upward to the thermosphere.

Wave models can propagate and converge to the antipode of the volcano, and continue to propagate. (Image by Prof. LEI’s team.)

(Written by HUANG Rui, edited by TONG Xinyang, USTC News Center)