News Topics
Hunga Tonga-Hunga Ha'apai Volcano Eruption Research
2022 - 2025
On 15 January 2022, the Hunga Tonga - Hunga Ha'apai (HTHH) volcano north of Tongatapu in the south west Pacific erupted. This eruption provided the opportunity to study the microphysical processes that occur when sulfur dioxide gas is emitted into the stratosphere. NOAA and CIRES scientists joined colleagues on La Réunion, an island in the Indian Ocean, to make in situ measurements in the sulfur plume deployed by high altitude research balloons. These efforts have resulted in scientific findings increasing in our understanding of the evolution of the volcanic contribution to stratospheric aerosol. CSL researchers have published or contributed to peer-reviewed science papers on these topics:
Field Campaigns
SPARC Activity
- Zhang, J., P. Wang, D. Kinnison, S. Solomon, J. Guan, K. Stone, and Y. Zhu, Stratospheric chlorine processing after the unprecedented Hunga Tonga eruption, Geophysical Research Letters, doi:10.1029/2024GL108649, 2024. After the eruption of Hunga Tonga–Hunga Ha'apai (HTHH) in January 2022, there was a substantial decrease in stratospheric hydrochloric acid (HCl) in the Southern Hemisphere mid latitudes in the latter part of 2022, hinting at potential chlorine activation. This study aims to comprehensively understand the significant loss of HCl following the HTHH eruption, utilizing satellite measurements and a global chemistry-climate model for analysis. The anomalies in 2022 show remarkable agreement between the modeled and measured data. Tracer-tracer relations between N2O and HCl suggest a substantial influence of chemical processing in the observed reduction of HCl, particularly during the austral winter of 2022. Upon further investigation into the role of chlorine gas-phase and heterogeneous chemistry, heterogeneous chemistry emerges as the primary driver for the chemical loss of HCl. The reaction between HOBr and HCl on sulfate aerosols is identifi ed as the dominant process leading to this loss.
- Li, C., Y. Peng, E. Asher, A. Baron, M. Todt, T. Thornberry, S. Evan, J. Brioude, P. Smale, R. Querel, K.H. Rosenlof, L. Zhou, J. Xu, K. Qie, J. Bian, O.B. Toon, Y. Zhu, and P. Yu, Microphysical simulation of the 2022 Hunga volcano eruption using a sectional aerosol model, Geophysical Research Letters, doi:10.1029/2024GL108522, 2024. The Hunga Tonga-Hunga Ha'apai (HTHH) submarine volcano erupted in January 2022, injecting a modest amount of SO2 but a record amount of water vapor relative to other eruptions into the mid-stratosphere observed in the satellite era. Our climate model simulations of the microphysical properties of the stratospheric aerosol suggest that the large water vapor injection caused the nucleation of many new sulfuric acid solution particles with small radius, enhancing coagulation efficiency. Rapid coagulation led to a peak radius of 0.2 µm by February and 0.4 µm by March of 2022. Our analysis finds that both particle optical efficiency and aerosol lifetime collectively exert an influence on normalized anomaly aerosol optical depth, explaining the high aerosol optical depth per unit emission of SO2 by HTHH, relative to the 1991 Pinatubo eruption.
- Zhang, J., D. Kinnison, Y. Zhu, X. Wang, S. Tilmes, K. Dube, and W. Randel, Chemistry contribution to stratospheric ozone depletion after the unprecedented water rich Hunga Tonga eruption, Geophysical Research Letters, doi:10.1029/2023GL105762, 2024. The January 2022 eruption of the Hunga Tonga-Hunga Ha'apai underwater volcano injected a large amount of water vapor and moderate amounts of sulfur dioxide into the stratosphere. Stratospheric ozone losses were observed following the eruption. The ozone layer in the stratosphere protects Earth's human being and biosphere from harmful ultraviolet light by absorbing the harmful portion of the radiation from the sun. We use computer simulation in this study to examine the impacts of chemical processes on the ozone layer from the volcanic materials. We find that chemistry is contributing up to 30% and 50% of the total ozone anomaly at Southern Hemisphere mid-latitudes winter and Antarctic spring respectively, with the majority of ozone changes owing to transport and dynamical processes.
- Asher, E., M. Todt, K. Rosenlof, T. Thornberry, R. Gao, G. Taha, P. Walter, S. Alvarez, J. Flynn, S. Davis, S. Evan, J. Brioude, J.-M. Metzger, D.F. Hurst, E. Hall, and K. Xiong, Unexpected rapid aerosol formation in the Hunga Tonga plume, Proceedings of the National Academy of Sciences, doi:10.1073/pnas.2219547120, 2023. The Hunga Tonga eruption on 15 January 2022 was the largest since that of Mt. Pinatubo in 1991. Repeated balloon soundings within two weeks of 15 January 2022 yielded measurements of the particle size distribution and sulfur dioxide and water vapor gases in the fresh Hunga Tonga plume. These observations better our understanding of this powerful and unusual eruption. In particular, these data provide information on the amount of sulfur injected into the upper atmosphere in consecutive eruptions on 13 and 15 January 2022, the altitude of the injections, the influence of water vapor on particle size, and the remarkably fast timeline for the oxidation of sulfur dioxide and particle formation within this plume.
- Davis, S.M., W. Randel, J. Augustine, B. Franz, N. Kramarova, T. LeBlanc, J.-P. Vernier, X. Wang, and M. Weber, Sidebar 2.2: Hunga Tonga–Hunga Haʻapai eruption [in "State of the Climate Report 2022"], Bulletin of the American Meteorological Society, doi:10.1175/2023BAMSStateoftheClimate.1, 2023.
- Evan, S., J. Brioude, K.H. Rosenlof, R.-S. Gao, R.W. Portmann, Y. Zhu, R. Volkamer, C.F. Lee, J.-M. Metzger, K. Lamy, P. Walter, S.L. Alvarez, J.H. Flynn, E. Asher, Michael Todt, S.M. Davis, T. Thornberry, H. Vömel, F.G. Wienhold, R.M. Stauffer, L. Mill´n, M.L. Santee, L. Froidevaux, and W.G. Read, Rapid ozone depletion after humidification of the stratosphere by the Hunga Tonga Eruption, Science, doi:10.1126/science.adg2551, 2023. The Hunga Tonga–Hunga Haʻapai submarine volcano in the South Pacific (20.55°S, 175.38°W) is the largest volcanic eruption since Mt. Pinatubo in 1991. It injected gas, ash, and water vapor as high as 50-55 km, and increased the total stratospheric water burden by ~10%. In-situ measurements of water vapor, aerosol, and ozone at the Maïdo Observatory on Réunion Island and remote sensing observations were used to study the evolution of ozone in the stratospheric plume prduced by the volcano. These show that chemical activation of chlorine species and destruction of ozone occured in the stratosphere in the first weeks after the eruption.
- Wang, X., W. Randel, Y. Zhu, S. Tilmes, J. Starr, W. Yu, R. Garcia, B. Toon, M. Park, D. Kinnison, J. Zhang, A. Bourassa, L. Rieger, T. Warnock, and J. Li, Stratospheric climate anomalies and ozone loss caused by Hunga Tonga volcanic eruption, Journal of Geophysical Research, doi:10.1029/2023JD039480, 2023. The submarine volcano Hunga Tonga-Hunga Ha'apai (HTHH) eruption on 15 January 2022 injected extreme amounts of water vapor (H2O) and a moderate amount of the aerosol precursor (SO2) into the Southern Hemisphere (SH) stratosphere. The H2O and aerosol perturbations have persisted and resulted in large-scale SH stratospheric cooling, equatorward shift of the Antarctic polar vortex, and slowing of the Brewer-Dobson circulation associated with a substantial ozone reduction in the SH winter midlatitudes. Chemistry-climate model simulations forced by realistic HTHH inputs of H2O and SO2 reproduce the observed stratospheric cooling and circulation effects, demonstrating the observed behavior is due to the volcanic influences. Furthermore, the combination of aerosol transport to polar latitudes and a cold polar vortex enhances springtime Antarctic ozone loss, consistent with the large observed Antarctic ozone hole in 2022.
- Yu, W., R. Garcia, J. Yue, A. Smith, X. Wang, W. Randel, Z. Qiao, Y. Zhu, V.L. Harvey, S. Tilmes, and M. Mlynczak, Mesospheric temperature and circulation response to the Hunga Tonga-Hunga-Ha'apai volcanic eruption, Geophysical Research Letters, doi:10.1029/2023JD039636, 2023. This work studies the impact of the Hunga Tonga-Hunga Ha'apai volcanic eruption, which took place on January 15, 2022, on the earth's mesosphere (55 km – 80 km). The eruption injected water vapor and SO2 into the stratosphere, which was followed by changes in the wind patterns in the stratosphere (16 km – 55 km). Concurrent with these changes, we observed unprecedented temperature changes in the mesosphere, with record highs and lows in August. We used climate model simulations to show that the changes in stratospheric winds were ultimately responsible for these record-breaking mesospheric temperatures. We found that the stronger winds in the stratosphere enhanced gravity wave breaking in the mesosphere, which led to changes in the circulation and thus the temperature. However, we could not find a clear mechanism for the changes observed in the stratosphere.
- Zhu, Y., C. Bardeen, S. Tilmes, M. Mills, X. Wang, V.L. Harvey, G. Taha, D. Kinnison, R.W. Portmann, P. Yu, K. Rosenlof, M. Avery, C. Kloss, C. Li, S. Glanville, L. Mill´n, T. Deshler, N. Krotkov, and O.B. Toon, Perturbations in stratospheric aerosol evolution due to the water-rich plume of the 2022 Hunga-Tonga eruption, Communications Earth & Environment, doi:10.1038/s43247-022-00580-w, 2023. The evolution of the Hunga Tonga aerosol was impacted by the large amount of water vapor also injected into the stratosphere by the eruption. The net effect is that the SO2 lifetime was reduced by a factor of two and the aerosols were larger. Modeling work suggests that the aerosol surface area will be enhanced for a significant amount of time following the January 2022 eruption, and possibly impact ozone chemistry in the Antarctic polar vortex the following year.
- Zhu, Y., R.W. Portmann, D. Kinnison, O.B. Toon, L. Millán, J. Zhang, H. Vömel, S. Tilmes, C.G. Bardeen, X. Wang, S. Evan, W.J. Randel, and K.H. Rosenlof, Stratospheric ozone depletion inside the volcanic plume shortly after the 2022 Hunga Tonga eruption, Atmospheric Chemistry and Physics, doi:10.5194/acp-23-13355-2023, 2023. The 2022 Hunga Tonga eruption injected a large amount of water into the stratosphere. Ozone depletion was observed inside the volcanic plume. Chlorine and water vapor injected by this eruption exceeded the normal range, which made the ozone chemistry during this event occur at a higher temperature than polar ozone depletion. Unlike polar ozone chemistry where chlorine nitrate is more important, hypochlorous acid plays a large role in the in-plume chlorine balance and heterogeneous processes.