Identification

Title

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

Abstract

Near-term in-plume ozone depletion was observed for about 10 d by the Aura Microwave Limb Sounder (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 (similar to 150 Tg) from the HTHH eruption, with similar to 0.0013 Tg injection of ClO (or similar to 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 s-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 2 d 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 similar to 5 Tg Cl was lifted into the stratosphere by the HTHH eruption in the form of NaCl, but only similar to 0.02 % of that remained as active chlorine in the stratosphere. Lightning NOx changes are probably not the reason for the HTHH initial in-plume O3 loss.

Resource type

document

Resource locator

Unique resource identifier

code

https://n2t.org/ark:/85065/d7736w28

codeSpace

Dataset language

eng

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geoscientificInformation

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title

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reference date

date type

publication

effective date

2016-01-01T00:00:00Z

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publication

effective date

2023-10-23T00:00:00Z

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None

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OpenSky Support

organisation name

UCAR/NCAR - Library

full postal address

PO Box 3000

Boulder

80307-3000

email address

opensky@ucar.edu

web address

http://opensky.ucar.edu/

name: homepage

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pointOfContact

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