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- Title
Pronounced Suppression and X‐Pattern Merging of Equatorial Ionization Anomalies After the 2022 Tonga Volcano Eruption.
- Authors
Aa, Ercha; Zhang, Shun‐Rong; Wang, Wenbin; Erickson, Philip J.; Qian, Liying; Eastes, Richard; Harding, Brian J.; Immel, Thomas J.; Karan, Deepak K.; Daniell, Robert E.; Coster, Anthea J.; Goncharenko, Larisa P.; Vierinen, Juha; Cai, Xuguang; Spicher, Andres
- Abstract
Following the 2022 Tonga Volcano eruption, dramatic suppression and deformation of the equatorial ionization anomaly (EIA) crests occurred in the American sector ∼14,000 km away from the epicenter. The EIA crests variations and associated ionosphere‐thermosphere disturbances were investigated using Global Navigation Satellite System total electron content data, Global‐scale Observations of the Limb and Disk ultraviolet images, Ionospheric Connection Explorer wind data, and ionosonde observations. The main results are as follows: (a) Following the eastward passage of expected eruption‐induced atmospheric disturbances, daytime EIA crests, especially the southern one, showed severe suppression of more than 10 TEC Unit and collapsed equatorward over 10° latitudes, forming a single band of enhanced density near the geomagnetic equator around 14–17 UT, (b) Evening EIA crests experienced a drastic deformation around 22 UT, forming a unique X‐pattern in a limited longitudinal area between 20 and 40°W. (c) Thermospheric horizontal winds, especially the zonal winds, showed long‐lasting quasi‐periodic fluctuations between ±200 m/s for 7–8 hr after the passage of volcano‐induced Lamb waves. The EIA suppression and X‐pattern merging was consistent with a westward equatorial zonal dynamo electric field induced by the strong zonal wind oscillation with a westward reversal. Plain Language Summary: The extreme Tonga volcano eruption on 15 January 2022 triggered profound and prolonged disturbances in the equatorial ionosphere. Using ground‐based Global Navigation Satellite System total electron content and ionosonde data, low‐Earth orbiting Ionospheric Connection Explorer wind observations, and geostationary Global‐scale Observations of the Limb and Disk ultraviolet measurements of thermospheric and ionospheric airglow emission, we found volcano‐induced atmospheric Lamb waves as a plausible source of the observed pronounced deformation of equatorial ionization anomaly (EIA) in the American sector. This deformation was triggered by volcano‐induced wave passage through the region, even after these waves had traveled 12,000–16,000 km distance for over 10 hr. The typical double‐crested EIA morphology was severely deformed during both the daytime and nighttime. Daytime EIA crests exhibited a severe suppression of more than 10 TEC Unit (TECu) (1TECu = 1016 m−2) and an equatorward collapse around 14–17 UT (10–13 LT) especially for the southern crest. Nighttime EIA crests exhibited a unique X‐pattern with crests drastically merging in a narrow longitude region between 20 and 40°W around 22 UT (20 LT). These large EIA deformations were coincident, sharing spatial scales with long‐lasting oscillations of thermospheric zonal wind following the arrival of volcano‐induced waves in the American sector. This study sheds new light on the potential far‐reaching and long‐lasting atmosphere‐ionosphere‐thermosphere impacts from a catastrophic geological event. Key Points: Daytime equatorial ionization anomaly (EIA) crests eroded severely by 10+ TEC Unit and collapsed equatorward over 10° latitude, following the arrival of volcano‐induced Lamb wavesEIA crests exhibited a unique deformation after sunset with an X‐pattern merging in a longitudinally‐confined area between 20° and 40°WThermospheric zonal wind showed post‐volcanic oscillations of ±200 m/s that may explain the EIA suppression and X‐pattern via dynamo effect
- Subjects
THERMOSPHERE; VOLCANIC eruptions; GLOBAL Positioning System; ZONAL winds; LAMB waves; ATMOSPHERIC waves
- Publication
Journal of Geophysical Research. Space Physics, 2022, Vol 127, Issue 6, p1
- ISSN
2169-9380
- Publication type
Article
- DOI
10.1029/2022JA030527