Evolution of the Climate Forcing During the Two Years after the Hunga Tonga-Hunga Ha'apai Eruption

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May 11, 2024, 8:26:12 AM5/11/24

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https://essopenarchive.org/users/523044/articles/741323-evolution-of-the-climate-forcing-during-the-two-years-after-the-hunga-tonga-hunga-ha-apai-eruption

Authors

Mark Robin Schoeberl,Yi Wang,Ghassan Taha,Daniel J Zawada,Rei Ueyama, Andrew E. Dessler

12 April 2024

Cite as: Mark Robin Schoeberl, Yi Wang, Ghassan Taha, et al. Evolution of the Climate Forcing During the Two Years after the Hunga Tonga-Hunga Ha'apai Eruption. ESS Open Archive . April 12, 2024.

DOI:10.22541/essoar.171288896.63010190/v1

Abstract

We calculate the climate forcing for the two years after the January 15, 2022, Hunga Tonga-Hunga Ha’apai (Hunga) eruption. We use satellite observations of stratospheric aerosols, trace gases and temperatures to compute the tropopause radiative flux changes relative to climatology. Overall, the net downward radiative flux decreased compared to climatology. Although the Hunga stratospheric water vapor anomaly increases the downward infrared radiative flux, the solar flux reduction due to Hunga aerosol shroud dominates the net flux over most of the two-year period. Decreases in temperature produced by the Hunga stratospheric circulation changes contributes to the decrease in downward flux; however, the Hunga induced decrease in ozone increases the net short-wave downward flux creating small sub-tropical net flux increase in late 2022. Coincident with the aerosols settling out, the water vapor anomaly disperses, and circulation changes disappear so that the contrasting forcings all decrease together. By the end of 2023, most of the Hunga induced radiative forcing changes have disappeared. There is some disagreement in the satellite stratospheric aerosol optical depth (SAOD) which we view as a measure of the uncertainty; however, SAOD uncertainty does not alter our conclusion that, overall, aerosols dominate the radiative flux changes followed by temperature and ozone.