Global ROTI map focusing on the Asia-Oceania sector and two graphs showing Swarm C and Swarm B paths.
Global rate of total electron content Index (ROTI) maps focusing on Asia-Oceania sector at 11:30 UT on 15 January 2022 with overlapping Swarm C (blue) and Swarm B (red) paths. The iso-distance lines from eruption epicenter are marked with black circles. The green circle marks the anticipated wavefront propagation of atmospheric Lamb waves, which is generally in concert with the westbound phase extension of locally developed plasma irregularity features shown by high ROTI values. The right two subpanels show corresponding electron density variation as a function of geomagnetic latitudes along Swarm paths, which shows significant equatorial and low-latitude plasma bite-outs that were 2–3 orders of magnitude lower than reference levels from the day before (dotted lines) and after (dashed lines) the volcano eruption. Credit: Aa et al. [2022], Figure 4c (modified)
Editors’ Highlights are summaries of recent papers by AGU’s journal editors.
Source: Space Weather

The catastrophic Tonga volcano eruption on 15 January 2022 triggered giant atmospheric waves that propagated into and strongly impacted the global ionosphere.

Using multiple ground/satellite observations, Aa et al. [2022] found large-scale, intense ionospheric density depletions that appeared in different ways as a prominent ionospheric hole and as equatorial plasma bubbles. Driven by intense shock-acoustic wave impulses, the eruption created a large-amplitude ionospheric hole of more than 10 TEC units with a horizontal radius of 10-15 degrees above the epicenter around 40 minutes after the eruption. The authors also reported for the first time the presence of continuously triggered, strong postsunset equatorial plasma bubbles over the vast Asia-Oceania area that were anomalously beyond the climatological behavior in January. These plasma bubble effects followed the consecutive sweep of the dusk terminator and arrival of eruption-excited Lamb waves and covered a wide longitudinal range of about 150 degrees with a duration around 12 hours.

These results demonstrate far-reaching and long-lasting atmosphere-ionosphere impacts from a devastating natural disaster and highlight new ways in which surface conditions can impact the upper atmosphere.

Citation: Aa, E., Zhang, S.-R., Erickson, P. J., Vierinen, J., Coster, A. J., Goncharenko, L. P., et al. (2022). Significant ionospheric hole and equatorial plasma bubbles after the 2022 Tonga volcano eruption. Space Weather, 20, e2022SW003101.

—Huixin Liu, Editor, Space Weather  

Text © 2022. The authors. CC BY-NC-ND 3.0
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