Scientists have identified the highest volcanic plume ever recorded

An enlarged image of the eruption, taken by the Japanese satellite Himawari-8 at 05:40 UTC on January 15, 2022, about 100 minutes after the eruption began. Image source: Simon Proud / Uni Oxford, RALSpace NCEO / Japan Meteorological Agency. Credit: Simon Proud / Uni Oxford, RALSpace NCEO / Japan Meteorological Agency

Using satellite images, researchers in the Department of Physics and RAL Space at the University of Oxford have confirmed that the January 2022 eruption of the Hunga Tonga-Hunga Ha’apai volcano produced the highest plume ever recorded. The massive eruption is also the first directly observed to have penetrated the mesosphere into the atmosphere. The results were published today in the journal Sciences.

On January 15, 2022, the Hong Tonga-Hungga Hawapai volcano, an undersea volcano in the Tonga archipelago in the South Pacific, violently erupted. The explosion was one of the most powerful ever observed, sending shock waves around the world and causing a devastating tsunami that left thousands homeless. A towering plume of ash and water was spewed into the atmosphere – but until now, scientists lacked an accurate way to measure how high that plume was.

Usually, the height of a volcanic plume can be estimated by measuring the temperature recorded at the top by infrared based satellites and comparing this to a reference vertical temperature profile. This is because in the troposphere (the first and lowest layer of Earth’s atmosphere), the temperature decreases with altitude. But if the eruption is so large that the plume penetrates the next layer of the atmosphere (the stratosphere), this method becomes obscure because the temperature begins to increase again with altitude (due to the ozone layer absorbing solar ultraviolet radiation).






An animation of the eruption seen by the GOES-17 weather satellite. Credit: Simon Proud and Simeon Schmauß / Uni Oxford, RALSpace NCEO / NOAA

To get around this problem, the researchers used a new method based on a phenomenon called the “parallax effect”. This is the apparent difference in the position of the object when viewed from multiple lines of sight. You can see this for yourself by closing your right eye, extending one hand and holding the thumb up. If you switch eyes afterward, so that your left is closed and your right is open, your thumb will appear to move slightly against the background. By measuring this apparent change in position and combining that with the known distance between your eyes, you can calculate the distance to your thumb.

The site of the Tonga volcano is covered by three geostationary weather satellites, so the researchers were able to apply a parallax effect to the captured aerial images. Crucially, during the eruption itself, satellites recorded images every 10 minutes, allowing rapid changes in the plume’s path to be documented.

Scientists have identified the highest volcanic plume ever recorded

Full Earth disk seen by Japanese satellite Himawari-8, volcanic eruption at lower right. Image credit: Simon Proud / Uni Oxford, RALSpace NCEO / Japan Meteorological Agency. Credit: Simon Proud / Uni Oxford, RALSpace NCEO / Japan Meteorological Agency

The results showed that the plume reached a height of 57 kilometers at its maximum extent. This is much higher than previous record holders: the 1991 eruption of Mount Pinatubo in the Philippines (40 km at its highest point), and the 1982 eruption of El Chichon in Mexico (31 km). It also makes the plume the first observational evidence of a volcanic eruption injecting material through the stratosphere and directly into the mesosphere, which begins about 50 km above the Earth’s surface.






Animation showing the calculated height of the eruption using data from three weather satellites. Credit: Simeon Schmaus / Japan Meteorological Agency / Korea Meteorological Administration / National Oceanic and Atmospheric Administration.

Lead author Dr Simon Proud (University of Oxford, RAL Space and National Center for Earth Observation) said, “It is an unusual result because we have never seen a cloud of any type this long before. Moreover, being able to estimate the height the way we did (using the parallax method) It’s only possible now that we have good satellite coverage. It wasn’t possible a decade or so ago.”

Oxford researchers now plan to create an automated system for calculating the heights of volcanoes using the parallax method. Co-author Dr. Andrew Prata from the Subsection of Atmospheric, Oceanic and Planetary Physics added, “We would also like to apply this technique to other eruptions and develop a data set of plume heights that can be used by volcanologists and atmospheric scientists to model the dispersal of volcanic ash in the atmosphere.” More Questions The scientific we would like to understand is: Why did the Tonga plume rise so high? What are the climatic effects of this volcanic eruption? And what exactly is the plume formed?”

Scientists have identified the highest volcanic plume ever recorded

An enlarged image of the eruption, taken by the Japanese satellite Himawari-8 at 04:50 UTC on January 15, 2022, about 50 minutes after the eruption began. Image source: Simon Proud / Uni Oxford, RALSpace NCEO / Japan Meteorological Agency. Credit: Simon Proud / Uni Oxford, RALSpace NCEO / Japan Meteorological Agency

Besides the University of Oxford, the study also included the Rutherford Appleton Laboratory and the National Center for Earth Observation in Harwell, and the Munich University of Applied Sciences. The research paper “Hungga Tonga-Hung Hapai volcano eruption in January 2022 that reached the mesosphere” was published in Sciences.

more information:
Simon R. Proud, the eruption of the Hongga Tonga-Hung Hapai volcano in January 2022 reached the mesosphere, Sciences (2022). DOI: 10.1126/science.abo4076. www.science.org/doi/10.1126/science.abo4076

Provided by Oxford University

the quote: Scientists identify highest volcanic plume ever recorded (2022, November 3) Retrieved November 4, 2022 from https://phys.org/news/2022-11-scientists-highest-ever-volcanic-plume.html

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