Stratospheric Ozone Changes From Explosive Tropical Volcanoes: Modeling and Ice Core Constraints

Ming, Alison; Winton, V. Holly L.; Keeble, James; Abraham, N. L.; Dalvi, Mohit; Griffiths, Paul; Caillon, Nicolas; Jones, A. E.; Mulvaney, Robert; Savarino, Joël; Frey, M. M.; Yang, Xin

doi:10.1029/2019jd032290

Cited by 19 publications

(20 citation statements)

References 91 publications

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“…~0.47, similar to the ratios simulated inMing et al, 2020, andBrenna et al, 2020 and smaller than the ratio simulated inCadoux et al, 2015. HAL10 has a SO2 injection similar to 1991 Pinatubo and a 10 times smaller flux of HCl and HBr than HAL56, resulting in a HCl:SO2 molar ratio of ~0.26, very close to the estimated stratospheric injection ratio for Mt.…”

supporting

confidence: 72%

“…These CTM studies used prescribed wind fields and, as a result, do not include the important interactive feedbacks of radiation and dynamics which alter the transport of tracers and thus the composition of the atmosphere. Ming et al, (2020) simulated explosive tropical eruptions in the UM-UKCA interactive https://doi.org/10.5194/acp-2020-1110 Preprint. Discussion started: 6 November 2020 c Author(s) 2020.…”

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confidence: 99%

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Co-emission of volcanic sulfur and halogens amplifies volcanic effective radiative forcing

Staunton-Sykes¹,

Aubry²,

Shin³

et al. 2020

Preprint

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Abstract. The evolution of volcanic sulfur and the resulting radiative forcing following explosive volcanic eruptions is well understood. Petrological evidence suggests that significant amounts of halogens may be co-emitted alongside sulfur in some explosive volcanic eruptions, and satellite evidence indicates that detectable amounts of these halogens may reach the stratosphere. In this study, we confront an aerosol-chemistry-climate model with four stratospheric volcanic eruption emission scenarios (56 Tg SO2 ± 15 Tg HCl & 0.086 Tg HBr and 10 Tg SO2 ± 1.5 Tg HCl & 0.0086 Tg HBr) in order to understand how co-emitted halogens may alter the life cycle of volcanic sulfur, stratospheric chemistry and the resulting radiative forcing. The eruption sizes simulated in this work are hypothetical Volcanic Explosivity Index (VEI) 7 (e.g. 1257 Mt. Samalas) and VEI 6 (e.g. 1991 Mt. Pinatubo) eruptions, representing 1 in 500–1000 year and 1 in 50–100 year events respectively, with plausible amounts of co-emitted halogens based on satellite observations and volcanic plume modelling. We show that co-emission of volcanic halogens and sulfur into the stratosphere increases the volcanic ERF by 24–30 % compared to sulfur-only emission. This is caused by an increase in both the forcing from volcanic aerosol-radiation interactions (ERFari) and composition of the stratosphere (ERFclear,clean). Volcanic halogens catalyse the destruction of stratospheric ozone which results in significant stratospheric cooling (1.5–3 K); counteracting the typical stratospheric radiative heating from volcanic sulfate aerosol. The ozone induced stratospheric cooling prevents aerosol self-lofting and keeps the volcanic aerosol lower in the stratosphere with a shorter lifetime, resulting in reduced growth due to condensation and coagulation and smaller peak global-mean effective radius compared to sulfur-only simulations. The smaller effective radius found in both co-emission scenarios is closer to the peak scattering efficiency radius of sulfate aerosol, thus, co-emission of halogens results in larger peak global-mean ERFari (6–8 %). Co-emission of volcanic halogens results in significant stratospheric ozone, methane and water vapour reductions, resulting in significant increases in peak global-mean ERFclear,clean (> 100 %), predominantly due to ozone loss. The dramatic global-mean ozone depletion simulated in both co-emission simulations (22 %, 57 %) would result in very high levels of UV exposure on the Earth's surface, with important implications for society and the biosphere. This work shows for the first time that co-emission of plausible amounts of volcanic halogens can amplify the volcanic ERF in simulations of explosive eruptions; highlighting the need to include volcanic halogens fluxes when simulating the climate impacts of past or future eruptions and providing motivation to better quantify the degassing budgets and stratospheric injection estimates for volcanic eruptions.

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supporting

confidence: 72%

mentioning

confidence: 99%

Co-emission of volcanic sulfur and halogens amplifies volcanic effective radiative forcing

Staunton-Sykes¹,

Aubry²,

Shin³

et al. 2020

Preprint

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“…It has been proposed that this spring ozone maximum, also seen at other high-latitude locations (e.g. Monks, 2000), is attributable to reduced ozone photo-dissociation and dry deposition in winter, balanced by increased stratospheric ozone intrusions in spring following the break-up of the polar vortex in the lower stratosphere (e.g. Laurila, 1999;Helmig et al, 2007a, b).…”

Section: Introductionmentioning

confidence: 94%

Pan-Arctic surface ozone: modelling vs. measurements

et al. 2020

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Abstract. Within the framework of the International Arctic Systems for Observing the Atmosphere (IASOA), we report a modelling-based study on surface ozone across the Arctic. We use surface ozone from six sites – Summit (Greenland), Pallas (Finland), Barrow (USA), Alert (Canada), Tiksi (Russia), and Villum Research Station (VRS) at Station Nord (North Greenland, Danish realm) – and ozone-sonde data from three Canadian sites: Resolute, Eureka, and Alert. Two global chemistry models – a global chemistry transport model (parallelised-Tropospheric Offline Model of Chemistry and Transport, p-TOMCAT) and a global chemistry climate model (United Kingdom Chemistry and Aerosol, UKCA) – are used for model data comparisons. Remotely sensed data of BrO from the GOME-2 satellite instrument and ground-based multi-axis differential optical absorption spectroscopy (MAX-DOAS) at Eureka, Canada, are used for model validation. The observed climatology data show that spring surface ozone at coastal sites is heavily depleted, making ozone seasonality at Arctic coastal sites distinctly different from that at inland sites. Model simulations show that surface ozone can be greatly reduced by bromine chemistry. In April, bromine chemistry can cause a net ozone loss (monthly mean) of 10–20 ppbv, with almost half attributable to open-ocean-sourced bromine and the rest to sea-ice-sourced bromine. However, the open-ocean-sourced bromine, via sea spray bromide depletion, cannot by itself produce ozone depletion events (ODEs; defined as ozone volume mixing ratios, VMRs, < 10 ppbv). In contrast, sea-ice-sourced bromine, via sea salt aerosol (SSA) production from blowing snow, can produce ODEs even without bromine from sea spray, highlighting the importance of sea ice surface in polar boundary layer chemistry. Modelled total inorganic bromine (BrY) over the Arctic sea ice is sensitive to model configuration; e.g. under the same bromine loading, BrY in the Arctic spring boundary layer in the p-TOMCAT control run (i.e. with all bromine emissions) can be 2 times that in the UKCA control run. Despite the model differences, both model control runs can successfully reproduce large bromine explosion events (BEEs) and ODEs in polar spring. Model-integrated tropospheric-column BrO generally matches GOME-2 tropospheric columns within ∼ 50 % in UKCA and a factor of 2 in p-TOMCAT. The success of the models in reproducing both ODEs and BEEs in the Arctic indicates that the relevant parameterizations implemented in the models work reasonably well, which supports the proposed mechanism of SSA production and bromide release on sea ice. Given that sea ice is a large source of SSA and halogens, changes in sea ice type and extent in a warming climate will influence Arctic boundary layer chemistry, including the oxidation of atmospheric elemental mercury. Note that this work dose not necessary rule out other possibilities that may act as a source of reactive bromine from the sea ice zone.

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“…The dynamics of the stratosphere have previously been shown to be well represented in this model, and it has an internally generated Quasi-Biennial Oscillation (QBO; Osprey et al, 2013) The model includes the fully interactive stratospheric GLOMAP-mode aerosol scheme, which simulates microphysical processes including the formation, growth, transport, and loss of aerosol (Dhomse et al, 2014). GLOMAP-mode also calculates aerosol optical properties online, which are used to calculate direct and indirect radiative effects (Mulcahy et al, 2020).…”

Section: Model Descriptionmentioning

confidence: 99%

Co-emission of volcanic sulfur and halogens amplifies volcanic effective radiative forcing

et al. 2021

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Abstract. The evolution of volcanic sulfur and the resulting radiative forcing following explosive volcanic eruptions is well understood. Petrological evidence suggests that significant amounts of halogens may be co-emitted alongside sulfur in some explosive volcanic eruptions, and satellite evidence indicates that detectable amounts of these halogens may reach the stratosphere. In this study, we utilise an aerosol–chemistry–climate model to simulate stratospheric volcanic eruption emission scenarios of two sizes, both with and without co-emission of volcanic halogens, in order to understand how co-emitted halogens may alter the life cycle of volcanic sulfur, stratospheric chemistry, and the resulting radiative forcing. We simulate a large (10 Tg of SO2) and very large (56 Tg of SO2) sulfur-only eruption scenario and a corresponding large (10 Tg SO2, 1.5 Tg HCl, 0.0086 Tg HBr) and very large (56 Tg SO2, 15 Tg HCl, 0.086 Tg HBr) co-emission eruption scenario. The eruption scenarios simulated in this work are hypothetical, but they are comparable to Volcanic Explosivity Index (VEI) 6 (e.g. 1991 Mt Pinatubo) and VEI 7 (e.g. 1257 Mt Samalas) eruptions, representing 1-in-50–100-year and 1-in-500–1000-year events, respectively, with plausible amounts of co-emitted halogens based on satellite observations and volcanic plume modelling. We show that co-emission of volcanic halogens and sulfur into the stratosphere increases the volcanic effective radiative forcing (ERF) by 24 % and 30 % in large and very large co-emission scenarios compared to sulfur-only emission. This is caused by an increase in both the forcing from volcanic aerosol–radiation interactions (ERFari) and composition of the stratosphere (ERFclear,clean). Volcanic halogens catalyse the destruction of stratospheric ozone, which results in significant stratospheric cooling, offsetting the aerosol heating simulated in sulfur-only scenarios and resulting in net stratospheric cooling. The ozone-induced stratospheric cooling prevents aerosol self-lofting and keeps the volcanic aerosol lower in the stratosphere with a shorter lifetime. This results in reduced growth by condensation and coagulation and a smaller peak global-mean effective radius compared to sulfur-only simulations. The smaller effective radius found in both co-emission scenarios is closer to the peak scattering efficiency radius of sulfate aerosol, and thus co-emission of halogens results in larger peak global-mean ERFari (6 % and 8 %). Co-emission of volcanic halogens results in significant stratospheric ozone, methane, and water vapour reductions, resulting in significant increases in peak global-mean ERFclear,clean (> 100 %), predominantly due to ozone loss. The dramatic global-mean ozone depletion simulated in large (22 %) and very large (57 %) co-emission scenarios would result in very high levels of UV exposure on the Earth's surface, with important implications for society and the biosphere. This work shows for the first time that co-emission of plausible amounts of volcanic halogens can amplify the volcanic ERF in simulations of explosive eruptions. It highlights the need to include volcanic halogen emissions when simulating the climate impacts of past or future eruptions, as well as the necessity to maintain space-borne observations of stratospheric compounds to better constrain the stratospheric injection estimates of volcanic eruptions.

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Stratospheric Ozone Changes From Explosive Tropical Volcanoes: Modeling and Ice Core Constraints

Cited by 19 publications

References 91 publications

Co-emission of volcanic sulfur and halogens amplifies volcanic effective radiative forcing

Co-emission of volcanic sulfur and halogens amplifies volcanic effective radiative forcing

Pan-Arctic surface ozone: modelling vs. measurements

Co-emission of volcanic sulfur and halogens amplifies volcanic effective radiative forcing

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