| Autor: |
Zhu, Yunqian, Portmann, Robert W., Kinnison, Douglas, Toon, Owen Brian, Millán, Luis, Zhang, Jun, Vömel, Holger, Tilmes, Simone, Bardeen, Charles G., Wang, Xinyue, Evan, Stephanie, Randel, William J., Rosenlof, Karen H. |
| Předmět: |
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| Zdroj: |
Atmospheric Chemistry & Physics; 2023, Vol. 23 Issue 20, p13355-13367, 13p |
| Abstrakt: |
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 (∼ 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 HO x and ClO x cycles and their interactions. Aside from the gas-phase chemistry, the heterogeneous reaction rate for HOCl + HCl → Cl 2 + H 2 O increases to 10 4 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 + ClONO 2 is more important. The large water injection causes relative humidity over ice to increase to 70 %–100 %, decreases the H 2 SO 4 / H 2 O 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 ∼ 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 NO x changes are probably not the reason for the HTHH initial in-plume O 3 loss. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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