Periodic Reporting for period 1 - SOLVE (Stratospheric Ozone Loss from Volcanic Eruptions)
Okres sprawozdawczy: 2021-11-01 do 2023-10-31
The ozone layer in the stratosphere is essential in protecting life on Earth from harmful UV irradiation. Small changes in ozone layer thickness can cause significant damage to human health and agriculture. Knowing the methods and causes for ozone depletion is therefore critical. Concerns that may impact the stratospheric ozone layer have emerged: explosive volcanic eruptions with significant halogen content, climate change and increased convection, and violations to the Montreal Protocol that limits the use of ozone depleting substances. Importantly, in the future, the largest perturbation to the ozone layer could be caused by volcanic eruptions. Explosive volcanic eruptions can alter stratospheric composition and chemistry, influencing the stratospheric ozone layer. The background composition of the stratosphere is central in determining the impact changes like a volcanic eruption will have on the chemistry and future composition. The widespread use of anthropogenic chlorine- and bromine-containing compounds through the emissions of chlorofluorocarbons (CFCs) and halons has been the cause of ozone depletion as observed over the polar regions as ozone holes. The Montreal Protocol and its amendments banning the CFCs and other ozone-depleting substances have been largely successful, but the long lifetimes of these compounds mean that full recovery of the ozone layer is still many decades away, and they are still present in the background stratosphere. Large explosive volcanic eruptions have the potential to alter the spatiotemporal profiles of the ozone column through changes in trace gas composition and aerosol loading of the stratosphere. Along with sulphur compounds, volcanic eruptions can inject halogens into the stratosphere, potentially leading to sudden and dramatic ozone losses on a hemispheric scale. This is a complex chemical system, involving heterogenous processes as well as gas-phase reactions varying with altitude.
The objectives of this project are to evaluate the impact on stratospheric composition, specifically ozone, from volcanic eruptions. Different chemical species can be injected into the stratosphere from volcanic eruptions and they have different impacts. Using 3-dimensional chemistry-climate modelling the impacts of halogen injection from volcanic eruptions into the stratosphere, the sensitivity toward latitude and season of the eruption in both contemporary and future climate scenarios will be elucidated. Investigating the chemistry of selected Bromine species that are present in the atmosphere, using both laboratory and quantum chemical calculations of the central reactions is another objective of this project. The results from both laboratory and theoretical work can then be implemented in the modelling achieving a better understanding of the background stratospheric composition and impacts of changes.
The objectives of this project are to evaluate the impact on stratospheric composition, specifically ozone, from volcanic eruptions. Different chemical species can be injected into the stratosphere from volcanic eruptions and they have different impacts. Using 3-dimensional chemistry-climate modelling the impacts of halogen injection from volcanic eruptions into the stratosphere, the sensitivity toward latitude and season of the eruption in both contemporary and future climate scenarios will be elucidated. Investigating the chemistry of selected Bromine species that are present in the atmosphere, using both laboratory and quantum chemical calculations of the central reactions is another objective of this project. The results from both laboratory and theoretical work can then be implemented in the modelling achieving a better understanding of the background stratospheric composition and impacts of changes.
Model simulations of the impact of volcanic eruptions on the stratosphere revealed the impact of latitude, season and content of the volcanically injected material into the stratosphere.
One publication investigated the sensitivity of stratospheric ozone to latitude, season and halogen content of an eruption in the present-day atmosphere (Østerstrøm et al., Sci. Rep. (2023), DOI: 10.1038/s41598-023-32574-9).
The unprecedented eruption of the submarine Hunga volcano in January 2022 is the focus of a second publication describing the global stratospheric changes and impacts in the first year following the eruption (Wilmouth et al., PNAS (2023), DOI: 10.1073/pnas.2301994120).
Ongoing work on the impact of volcanic eruptions in the future with varying climate scenarios is being continued along with the work on the Hunga eruption, as I complete the return phase of the project.
One publication investigated the sensitivity of stratospheric ozone to latitude, season and halogen content of an eruption in the present-day atmosphere (Østerstrøm et al., Sci. Rep. (2023), DOI: 10.1038/s41598-023-32574-9).
The unprecedented eruption of the submarine Hunga volcano in January 2022 is the focus of a second publication describing the global stratospheric changes and impacts in the first year following the eruption (Wilmouth et al., PNAS (2023), DOI: 10.1073/pnas.2301994120).
Ongoing work on the impact of volcanic eruptions in the future with varying climate scenarios is being continued along with the work on the Hunga eruption, as I complete the return phase of the project.
Both publications are likely to be informative for the scientific community, specifically informing the WMO ozone assessment reports and IPCC climate assessments in evaluating the impact form volcanic eruptions now and in a future changing climate.
Ongoing work from this project will provide additional results relevant for the same groups. Understanding how the atmosphere changes following natural perturbations can help us understand the Earth-atmosphere-climate system better and aid in better predictions of human-caused changes to the climate of our planet.
Ongoing work from this project will provide additional results relevant for the same groups. Understanding how the atmosphere changes following natural perturbations can help us understand the Earth-atmosphere-climate system better and aid in better predictions of human-caused changes to the climate of our planet.