When the Hunga Tonga-Hunga Ha’apai volcano erupted on January 15, 2022 within the South Pacific, it produced a shock wave felt around the globe and triggered tsunamis in Tonga, Fiji, New Zealand, Japan, Chile, Peru and the USA. It additionally modified the chemistry and dynamics of the stratosphere within the yr following the eruption, resulting in unprecedented losses within the ozone layer of as much as 7% over giant areas of the Southern Hemisphere, in keeping with a current research printed within the Proceedings of the Nationwide Academy of Sciences (PNAS) from the Harvard John A. Paulson Faculty of Engineering and Utilized Sciences (SEAS) and the College of Maryland.
Driving these atmospheric modifications, in keeping with the analysis, was the sheer quantity of water vapor injected into the stratosphere by the undersea volcano. The situation of the stratosphere is roughly 8 – 30 miles above Earth’s floor and is the place the protecting ozone layer resides.
“The Hunga Tonga-Hunga Ha’apai eruption was really extraordinary in that it injected about 300 billion kilos of water into the usually dry stratosphere, which is simply a fully unbelievable quantity of water from a single occasion,” stated David Wilmouth, a challenge scientist at SEAS and first writer of the paper.
“This eruption put us in uncharted territory,” stated Ross Salawitch, professor on the College of Maryland’s Earth System Science Interdisciplinary Heart and co-author of the research. “We’ve by no means seen, within the historical past of satellite tv for pc data, this a lot water vapor injected into the environment and our paper is the primary that appears on the downstream penalties over broad areas of each hemispheres within the months following the eruption utilizing satellite tv for pc knowledge and a worldwide mannequin.”
The Hunga Tonga-Hunga Ha’apai eruption was the most important explosion ever recorded within the environment. The eruption hurled aerosols and gases deep into the stratosphere. Some materials reached the decrease mesosphere, greater than 30 miles above the Earth’s floor, altitudes by no means recorded from a volcanic eruption. Earlier research discovered that the eruption elevated water vapor within the stratosphere by 10% worldwide, with even greater concentrations in some areas of the Southern Hemisphere.
Wilmouth, Salawitch and the remainder of the analysis workforce used knowledge from the Microwave Limb Sounder (MLS) aboard the NASA Aura satellite tv for pc, to trace not solely how that water vapor moved throughout the globe but additionally monitor temperature and ranges of chlorine monoxide (ClO), ozone (O3), nitric acid (HNO3), and hydrogen chloride (HCl) within the stratosphere for the yr following the eruption. They then in contrast these measurements to knowledge collected by MLS from 2005 to 2021 previous to the eruption.
The workforce discovered that the injection of water vapor and sulfur dioxide (SO2) modified each the chemistry and the dynamics of the stratosphere.
When it comes to chemistry, the SO2 led to a rise of sulfate aerosols, which offered new surfaces for chemical reactions to happen.
“Sure reactions that may not occur in any respect or solely occur slowly can occur quicker if there are aerosols out there on which these reactions can happen,” stated Wilmouth. “The injection of SO2 from the volcano allowed sulfate aerosols to kind and the presence of water vapor led to the extra manufacturing of sulfate aerosols.”
The elevated sulfate aerosols and water vapor kicked off a sequence of occasions within the advanced atmospheric chemistry that led to widespread modifications within the concentrations of plenty of compounds, together with ozone.
The additional water vapor additionally had a cooling impact within the stratosphere, resulting in a change in circulation, which drove decreases in ozone within the southern hemisphere and a rise of ozone over the tropics.
The researchers discovered that the height lower in ozone occurred in October, 9 months after the eruption.
“We had this huge enhance in water vapor within the stratosphere with modest will increase in sulfate that set off a collection of occasions that led to vital modifications in temperature and circulation, ClO, HNO3, HCl, O3, and different gases,” Wilmouth stated.
Subsequent, the researchers hope to proceed the research by following the influence of the volcano into 2023 and past because the water vapor strikes from the tropics and midlatitudes to the Southern Hemisphere pole, the place it has the potential to amplify ozone losses within the Antarctic. The water vapor is predicted to remain elevated within the stratosphere for a interval of a number of years.