(ORDO NEWS) — Scientists have re-evaluated the height of the eruption of the Khunga-Tonga-Hunga-Haapai volcano, which occurred in early 2022. It turned out to be a record high: the ash plume rose above 50 kilometers and reached the mesosphere.
Hunga Tonga and Hunga Haapai are a pair of small uninhabited islands in the Polynesian Tonga archipelago.
They represent parts of the cone of the underwater volcano Hunga-Tonga-Hunga-Haapai protruding above the surface, which remains highly active.
Its last eruption occurred in mid-January 2022, it created a powerful tsunami and led to human casualties.
Now scientists from the University of Oxford have looked at this catastrophe from a new angle, using data from satellite observations.
Such work made it possible to more accurately estimate the height of the ash plume ejected by the eruption.
It turned out that he had risen to a height of 57 kilometers, having overcome the lower layers of the earth’s atmosphere – the troposphere and stratosphere – and reached the mesosphere.
As a rule, the plume is estimated based on temperature measurements, since within the troposphere it normally decreases with altitude.
However, in the stratosphere, everything happens the other way around, and the temperature rises again.
This makes such calculations difficult for such a powerful eruption as the event of early 2022 turned out to be.
Therefore, Simon Proud and his colleagues used the parallax method – changes in the apparent position of an object when viewed from different points.
The scientists relied on survey data taken by several weather satellites from geostationary orbit.
Calculations showed that the height of the Hunga-Tonga-Hunga-Haapai ash plume reached 57 kilometers – much more than the previous record holder for such measurements, the eruption of the Philippine volcano Pinatubo in 1991 (40 kilometers).
According to the authors, this plume was the first to reach the Earth‘s mesosphere, starting at a height of about 50 kilometers.
Based on their formulas, Proud and his colleagues are going to develop an algorithm for automatically estimating the height of volcanic plumes using the parallax method.
This will provide a broad base that will be useful for refining models of atmospheric dynamics, the contribution of such events to climate change, as well as a better understanding of the eruptions themselves and the associated emissions of ash and gases.
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