Impact of the 2022 Hunga Tonga Volcano on Global Middle Atmosphere Water Vapour and Climate Implications

The 2022 Hunga Tonga–Hunga Haʻapai volcano eruption was a major global event, injecting a significant volume of water vapour into the stratosphere and contributing to an estimated 10% increase in global stratospheric water vapour. Due to the fact that water vapour is the most powerful greenhouse gas not directly controlled by anthropogenic activities, this has implications on the radiative heating at the surface and thus surface temperatures.

Due to the elevated location of the water vapour anomaly, obtaining measurements of the mixing ratio of the anomaly is challenging. Employing two microwave radiometers, operated by the Institute of Applied Physics (IAP) in Bern, Switzerland, profiles of water vapour mixing ratio are presented at two locations: Switzerland and Svalbard. Analysis of data from these points, dating back to 2010, reveals the anomaly's characteristics and its influence on surface radiative heating.

Our findings are contextualized with additional data from satellite observations, in-situ instruments, and other ground-based microwave radiometers. This comprehensive approach allows us to explore the wider implications of the Hunga Tonga eruption on the climate, particularly in relation to 2023, a year noted as the hottest on record.