Overview of the SPARC Hunga Tonga Hunga Ha’Apai Stratospheric Impacts Activity (Invited Presentation)

The Hunga Tonga Hunga Ha’apai (HTHH) Impacts activity was established by WCRP/SPARC (Stratosphere-troposphere Processes And their Role in Climate) to examine impacts of the HTHH eruption of January 2022. HTHH was the most explosive volcanic eruption in the satellite era, and the water-rich plume presents an opportunity to understand the impacts on the stratosphere and climate system of a large magnitude explosive phreatomagmatic eruption. The SPARC HTHH activity is a community project focused on synthesis of observations and coordination of multi-model evaluations, with a goal to write a comprehensive HTHH Impacts Report by 2025 (for input to the 2026 UNEP/WMO Ozone Assessment). Research topics include short- and long-term evolution of the water and aerosol plumes, effects on the atmospheric circulation, transport and chemistry (including polar and midlatitude ozone changes), whole atmosphere influences and radiative/climate effects. This talk will give an update on project status and activities, including some examples of ongoing work.