The January 2022 Hunga Tonga-Hunga Ha'apai volcanic eruption injected a relatively small amount of sulfur dioxide, but significantly more water into the stratosphere than previously seen in the modern satellite record. This paper shows that the large amount of water resulted in large perturbations to stratospheric aerosol evolution. A climate model simulation reproduces the observed enhanced water vapor, which increases hydroxide and halves the sulfur dioxide lifetime. Subsequent coagulation creates larger sulfate particles, doubling the stratospheric aerosol optical depth. The eruption will enhance aerosol surface area and water vapor near the polar vortex until at least October 2022, impacting the climate system.

Yunqian Zhu, Charles G. Bardeen, Simone Tilmes, Michael J. Mills, Xinyue Wang, V. Lynn Harvey, Ghassan Taha, Douglas Kinnison, Robert W. Portmann, Pengfei Yu, Karen H. Rosenlof, Melody Avery, Corinna Kloss, Can Li, Anne S. Glanville, Luis Millán, Terry Deshler, Nickolay Krotkov, Owen B. Toon