Perturbation of Tropical Stratospheric Ozone Through Homogeneous and Heterogeneous Chemistry Due To Pinatubo

• Published in: Geophysical research letters 2023-08, Vol.50 (16), p.n/a
• Main Authors: Peng, Yifeng, Yu, Pengfei, Portmann, Robert W., Rosenlof, Karen H., Zhang, Jiankai, Liu, Cheng‐Cheng, Li, Jiangtao, Tian, Wenshou
• Format: Article
• Language: English
• Subjects: Anomalies; Atmospheric chemistry; Brewer‐Dobson circulation; Chemical reactions; Chemistry; Climate models; Eruptions; gas‐phase chemistry; heterogeneous chemistry; Nitrogen compounds; Ocean circulation; Oxidation; Oxides; Ozone; Ozone anomalies; Perturbation; Pinatubo aerosol; Sensitivity; Simulation; Stratosphere; Stratospheric chemistry; Sulfate aerosols; Sulfates; Sulfur dioxide; Tropical environments; tropical ozone; Upwelling; Volcanic activity; Volcanic eruptions; WACCM‐MAM3
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1029/2023GL103773

The Pinatubo eruption in 1991 injected 10–20 Tg SO2 into the stratosphere, which formed sulfate aerosols through oxidation. Our modeling results show that volcanic heating significantly perturbs the heterogeneous and homogeneous chemistry including NOx and HOx catalytic cycles in the tropical stratosphere. The simulated tropical chemical ozone tendency is positive at 20 mb while negative at 10 mb in the tropics. The simulated ozone chemical tendency is of the same magnitude as the dynamical ozone tendency caused by the accelerated tropical upwelling, but with the opposite sign. Our study finds that the tropical ozone chemical tendency due to homogeneous chemistry becomes more important than heterogeneous chemistry 3 months after eruption. Sensitivity simulations further suggest that the tropical ozone tendency through heterogeneous chemistry is saturated when the injected amount exceeds 2 Tg. Plain Language Summary In 1991, a large volcanic eruption injected 10–20 Tg SO2 into the stratosphere and perturbed the stratospheric chemistry and dynamics. In this study, we use a climate model to quantify the chemical and dynamical influence of the volcano on tropical stratospheric ozone. Model suggests that the ozone chemical tendency is positive around 28 km while negative around 35 km. Our study also suggests that both heterogeneous and homogeneous chemical reactions contribute to the ozone anomalies. With sensitivity studies, we show that the tropical ozone changes due to heterogeneous chemistry is saturated if the injected amount exceeds 2 Tg. Key Points The simulated ozone tendency due to chemistry is of the same order of magnitude but of the opposite sign than that due to dynamics The chemistry‐driven change in the tropical ozone tendency is dominated by the gas‐phase rather than heterogeneous chemistry The ozone tendency change due to heterogeneous chemistry is saturated when the injected SO2 amount exceeds 2 Tg