• 2022 Tonga Volcanic Eruption Induced Global Propagation of Ionospheric Disturbances via Lamb Waves 

      Zhang, Shun-Rong; Vierinen, Juha; Aa, Ercha; Goncharenko, Larisa P.; Erickson, Philip J.; Rideout, William; Coster, Anthea J.; Spicher, Andres (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-03-23)
      The Tonga volcano eruption at 04:14:45 UT on 2022-01-15 released enormous amounts of energy into the atmosphere, triggering very significant geophysical variations not only in the immediate proximity of the epicenter but also globally across the whole atmosphere. This study provides a global picture of ionospheric disturbances over an extended period for at least 4 days. We find traveling ionospheric ...
    • GNSS Observations of Ionospheric Variations During the 21 August 2017 Solar Eclipse 

      Coster, A. J.; Goncharenko, Larisa; Zhang, Shun-Rong; Erickson, P. J.; Rideout, William; Vierinen, Juha (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-11-20)
      On 21 August 2017, during daytime hours, a total solar eclipse with a narrow ∼160 km wide umbral shadow occurred across the continental United States. Totality was observed from the Oregon coast at ∼9:15 local standard time (LST) (17:20 UT) to the South Carolina coast at ∼13:27 LST (18:47 UT). A dense network of Global Navigation Satellite Systems (GNSS) receivers was utilized to produce total ...
    • Ionospheric bow waves and perturbations induced by the 21 August 2017 solar eclipse 

      Zhang, Shun-Rong; Erickson, Philip j.; Goncharenko, Larisa; Coster, Anthea; Rideout, William; Vierinen, Juha (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-12-04)
      During solar eclipses, the Moon's shadow causes a large reduction in atmospheric energy input, including not only the stratosphere but also the thermosphere and ionosphere. The eclipse shadow has a supersonic motion which is theoretically expected to generate atmospheric bow waves, similar to a fast‐moving river boat, with waves starting in the lower atmosphere and propagating into the ionosphere. ...
    • Pronounced Suppression and X-Pattern Merging of Equatorial Ionization Anomalies After the 2022 Tonga Volcano Eruption 

      Aa, Ercha; Zhang, Shun-Rong; Wang, Wenbing; Erickson, Philip J.; Qian, Liying; Eastes, Richard W.; Harding, Brian; Immel, Thomas; Karan, Deepak; Daniell, Robert E.; Coster, Anthea J.; Goncharenko, Larisa P.; Vierinen, Juha; Cai, Xuguang; Spicher, Andres (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-05-27)
      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 ...
    • Simultaneous Global Ionospheric Disturbances Associated With Penetration Electric Fields During Intense and Minor Solar and Geomagnetic Disturbances 

      Zhang, Shun-Rong; Nishimura, Yukitoshi; Vierinen, Juha-Pekka; Lyons, Larry R.; Knipp, Delores J.; Gustavsson, Björn Johan; Waghule, Bhagyashree V.; Erickson, Philip J.; Coster, Anthea J.; Aa, Ercha; Spicher, Andres (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-09-29)
      A new observational phenomenon, named Simultaneous Global Ionospheric Density Disturbance (SGD), is identified in GNSS total electron content (TEC) data during periods of three typical geospace disturbances: a Coronal Mass Ejection-driven severe disturbance event, a high-speed stream event, and a minor disturbance day with a maximum Kp of 4. SGDs occur frequently on dayside and dawn sectors, with ...
    • Traveling ionospheric disturbances and ionospheric perturbations associated with solar flares in September 2017 

      Zhang, Shun-Rong; Coster, Anthea; Erickson, Philip j.; Goncharenko, Larisa; Rideout, William; Vierinen, Juha (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-07-10)
      Solar flares provide strong impulsive radiation and energy injection to the sunlit upper atmosphere. The impact on the ionosphere is immense in spatial scale, and therefore, it is not immediately evident if dramatically elevated neutral heating can lead to excitation of acoustic gravity waves. Using primary observations from Global Navigation Satellite System differential TEC (total electron ...