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https://doi.org/10.5194/egusphere-2023-1334
https://doi.org/10.5194/egusphere-2023-1334
28 Jun 2023
 | 28 Jun 2023

Stratospheric ozone depletion inside the volcanic plume shortly after the 2022 Hunga Tonga eruption

Yunqian Zhu, Robert W. Portmann, Douglas Kinnison, Owen B. Toon, Luis Millán, Jun Zhang, Holger Vömel, Simone Tilmes, Charles G. Bardeen, Xinyue Wang, Stephanie Evan, William J. Randel, and Karen H. Rosenlof

Abstract. In-plume ozone depletion was observed for about ten days by Microwave Limb Sounder (Aura/MLS) right after the January 2022 Hunga Tonga-Hunga Ha’apai (HTHH) eruption. This work analyzes the dynamic and chemical causes of this ozone depletion. The results show that the large water injection (~150 Tg) from the HTHH eruption, with ~0.0013 Tg injection of ClO (or ~0.0009 Tg of HCl), causes ozone loss due to strongly enhanced HOx and ClOx cycles and their interactions. Aside from the gas phase chemistry, the heterogeneous reaction rate for HOCl+HCl→Cl2+H2O increases to 104 cm-3 sec-1 and is a major cause of chlorine activation, making this event unique compared with the springtime polar ozone depletion where HCl+ClONO2 is more important. The large water injection causes relative humidity over ice to increase to 70 %–100 %, decreases the H2SO4/H2O binary solution weight percent to 35 % compared with the 70 % ambient value, and decreases the plume temperature by 2–6 K. These changes lead to high heterogeneous reaction rates. Plume lofting of ozone-poor air is evident during the first two days after the eruption, but ozone concentrations quickly recover because its chemical lifetime is short at 20 hPa. With such a large seawater injection, we expect that ~5 Tg Cl was lifted into the stratosphere by the HTHH eruption in the form of NaCl, but only ~0.02 % of that remained as active chlorine in the stratosphere. lightning NOx changes are not the reason for the HTHH initial in-plume O3 loss.

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Journal article(s) based on this preprint

23 Oct 2023
Stratospheric ozone depletion inside the volcanic plume shortly after the 2022 Hunga Tonga eruption
Yunqian Zhu, Robert W. Portmann, Douglas Kinnison, Owen Brian Toon, Luis Millán, Jun Zhang, Holger Vömel, Simone Tilmes, Charles G. Bardeen, Xinyue Wang, Stephanie Evan, William J. Randel, and Karen H. Rosenlof
Atmos. Chem. Phys., 23, 13355–13367, https://doi.org/10.5194/acp-23-13355-2023,https://doi.org/10.5194/acp-23-13355-2023, 2023
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The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.

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The 2022 Hunga Tonga eruption injected a large amount of water into the stratosphere. Ozone...
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