Brominated VSLS and their influence on ozone under a changing climate
Very short-lived substances (VSLS) contribute as source gases significantly to the tropospheric and stratospheric bromine loading. At present, an estimated 25 % of stratospheric bromine is of oceanic origin. In this study, we investigate how climate change may impact the ocean–atmosphere flux of...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2017-09-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://www.atmos-chem-phys.net/17/11313/2017/acp-17-11313-2017.pdf |
| Summary: | Very short-lived substances (VSLS) contribute as source gases
significantly to the tropospheric and stratospheric bromine
loading. At present, an estimated 25 % of stratospheric
bromine is of oceanic origin. In this study, we investigate how
climate change may impact the ocean–atmosphere flux of brominated
VSLS, their atmospheric transport, and chemical transformations and
evaluate how these changes will affect stratospheric ozone over the
21st century.
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Under the assumption of fixed ocean water concentrations and RCP6.0
scenario, we find an increase of the ocean–atmosphere flux of
brominated VSLS of about 8–10 % by the end of the 21st
century compared to present day. A decrease in the tropospheric
mixing ratios of VSLS and an increase in the lower stratosphere are
attributed to changes in atmospheric chemistry and transport. Our
model simulations reveal that this increase is counteracted by
a corresponding reduction of inorganic bromine. Therefore the total
amount of bromine from VSLS in the stratosphere will not be changed by
an increase in upwelling. Part of the increase of VSLS in the tropical
lower stratosphere results from an increase in the corresponding
tropopause height. As the depletion of stratospheric ozone due to
bromine depends also on the availability of chlorine, we find the
impact of bromine on stratospheric ozone at the end of the 21st
century reduced compared to present day. Thus, these studies
highlight the different factors influencing the role of brominated
VSLS in a future climate. |
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| ISSN: | 1680-7316 1680-7324 |