(ORDO NEWS) — It has recently been confirmed that the eruption of the Hunga-Tonga-Hunga-Ha’apai volcano on Tonga at 04:14:45 UT on January 15 resulted in large-scale global disturbances in the Earth’s atmosphere.
Using data recorded by more than 5,000 Global Navigation Satellite System (GNSS) ground-based receivers located around the world, scientists at MIT’s Haystack Observatory and their international partners at the Arctic University of Norway observed significant evidence of atmospheric waves generated by the eruption and their ionospheric signatures.
At an altitude of 300 kilometers above the Earth’s surface for an extended period of time. These atmospheric waves were active for at least four days after the eruption and circled the globe three times. Ionospheric disturbances passed over the United States six times, first from west to east, and then in the opposite direction.
This volcanic event was extraordinarily powerful, releasing the energy equivalent of 1,000 atomic bombs of this size deployed in 1945. Scientists know that explosive volcanic eruptions and earthquakes can cause a series of atmospheric pressure waves, including acoustic waves, and that they can disturb the upper atmosphere several hundred kilometers above the epicenter.
Being over the ocean, they can cause tsunami waves and, consequently, perturbations in the upper atmosphere. The results of this eruption in Tonga surprised the international team, especially with their geographical extent and multi-day duration. These discoveries ultimately suggest new ways of communicating between atmospheric waves and the global ionosphere.
The authors believe that the perturbations are the effect of Lamb waves; these waves, named after the mathematician Horace Lamb, propagate at the speed of sound around the world without much reduction in amplitude.
Although located predominantly near the Earth’s surface, these waves can exchange energy with the ionosphere along complex paths. As the new paper says, “dominant Lamb waves have been previously recorded as an atmospheric response to the 1883 Krakatoa eruption and other geohazards. This study provides the first significant evidence of their long-term imprint in the global ionosphere.”
With support from the National Science Foundation, Haystack has been collecting global GNSS observations daily since 2000 to study important information about the total electron content. The observatory shares this data with the international geospatial community, enabling innovative research in a range of areas, from the effects of solar storms to low-level impacts.
A special form of space weather caused by ionospheric waves called traveling ionospheric perturbations (TPIs) is often driven by processes including sudden inputs of energy from the Sun, terrestrial weather, and anthropogenic disturbances. For example, Haystack scientists have used TID observations to provide the first evidence that solar eclipses can cause bow waves in the Earth’s atmosphere.
Lead author Shunrong Zhang says: “It is known that only strong solar storms can cause a global spread of TID in space for hours or even days; volcanic eruptions and earthquakes usually cause ionospheric disturbances only within thousands of kilometers.
Having discovered these significant ionospheric disturbances , caused by eruptions in space at very long distances, we have detected not only the generation of Lamb waves and their global propagation over several days (which is often tracked as sound waves on the ground to comply with the Comprehensive Nuclear-Test-Ban Treaty), but also a fundamental new physical process.
As a result, signals from the surface and from the lower atmosphere can produce a loud burst even in deep space.” In addition to these findings, Haystack’s scientists are continuing additional research into how the Tonga eruption caused severe space weather effects.
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