The eruption of the Hunga Tonga-Hunga Ha’apai volcano in January 2022 had a profound impact on the stratosphere’s chemistry and dynamics. This event, one of the largest volcanic explosions ever recorded, injected an unprecedented 300 billion pounds of water vapor into the stratosphere, which is typically dry and home to the protective ozone layer. The eruption’s effects were felt globally, resulting in up to 7% ozone loss over large parts of the Southern Hemisphere.
Researchers used data from the NASA Aura satellite’s Microwave Limb Sounder (MLS) to monitor the movement of water vapor and the levels of various gases in the stratosphere for a year post-eruption. They found that the combination of water vapor and sulfur dioxide (SO₂) significantly altered the stratosphere’s chemistry and dynamics. This change led to an increase in sulfate aerosols, providing new surfaces for chemical reactions, ultimately affecting the concentrations of compounds like ozone.
The additional water vapor caused cooling in the stratosphere, altering atmospheric circulation and driving ozone decreases in the Southern Hemisphere while increasing it over the tropics. The peak decrease in ozone occurred nine months after the eruption. The study, highlighting the eruption’s extensive impact, suggests the need for continued monitoring into 2023 and beyond, as the water vapor is expected to remain elevated in the stratosphere for several years.
https://phys.org/news/2023-11-massive-eruption-stratosphere-chemistry-dynamics.html