Future Arctic ozone recovery: the importance of chemistry and dynamics
Future trends in Arctic springtime total column ozone, and its chemical and dynamical drivers, are assessed using a seven-member ensemble from the Met Office Unified Model with United Kingdom Chemistry and Aerosols (UM-UKCA) simulating the period 1960–2100. The Arctic mean March total column ozon...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2016-09-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://www.atmos-chem-phys.net/16/12159/2016/acp-16-12159-2016.pdf |
| _version_ | 1811232400992108544 |
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| author | E. M. Bednarz A. C. Maycock A. C. Maycock A. C. Maycock N. L. Abraham N. L. Abraham P. Braesicke P. Braesicke P. Braesicke O. Dessens J. A. Pyle J. A. Pyle |
| author_facet | E. M. Bednarz A. C. Maycock A. C. Maycock A. C. Maycock N. L. Abraham N. L. Abraham P. Braesicke P. Braesicke P. Braesicke O. Dessens J. A. Pyle J. A. Pyle |
| author_sort | E. M. Bednarz |
| collection | DOAJ |
| description | Future trends in Arctic springtime total column ozone, and its chemical and
dynamical drivers, are assessed using a seven-member ensemble from the Met
Office Unified Model with United Kingdom Chemistry and Aerosols (UM-UKCA)
simulating the period 1960–2100. The Arctic mean March total column ozone
increases throughout the 21st century at a rate of
∼ 11.5 DU decade<sup>−1</sup>, and is projected to return to the 1980 level
in the late 2030s. However, the integrations show that even past 2060
springtime Arctic ozone can episodically drop by ∼ 50–100 DU below
the corresponding long-term ensemble mean for that period, reaching values
characteristic of the near-present-day average level. Consistent with the
global decline in inorganic chlorine (Cl<sub><i>y</i></sub>) over the century, the
estimated mean halogen-induced chemical ozone loss in the Arctic lower
atmosphere in spring decreases by around a factor of 2 between the periods
2001–2020 and 2061–2080. However, in the presence of a cold and strong
polar vortex, elevated halogen-induced ozone losses well above the
corresponding long-term mean continue to occur in the simulations into the
second part of the century. The ensemble shows a significant cooling trend in
the Arctic winter mid- and upper stratosphere, but there is less confidence
in the projected temperature trends in the lower stratosphere (100–50 hPa).
This is partly due to an increase in downwelling over the Arctic polar cap in
winter, which increases transport of ozone into the polar region as well as
drives adiabatic warming that partly offsets the radiatively driven
stratospheric cooling. However, individual winters characterised by
significantly suppressed downwelling, reduced transport and anomalously low
temperatures continue to occur in the future. We conclude that, despite the
projected long-term recovery of Arctic ozone, the large interannual dynamical
variability is expected to continue in the future, thereby facilitating
episodic reductions in springtime ozone columns. Whilst our results suggest
that the relative role of dynamical processes for determining Arctic
springtime ozone will increase in the future, halogen chemistry will remain a
smaller but non-negligible contributor for many decades to come. |
| first_indexed | 2024-04-12T11:02:35Z |
| format | Article |
| id | doaj.art-a43562468b5e49488ace9b1d6df4abc2 |
| institution | Directory Open Access Journal |
| issn | 1680-7316 1680-7324 |
| language | English |
| last_indexed | 2024-04-12T11:02:35Z |
| publishDate | 2016-09-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Chemistry and Physics |
| spelling | doaj.art-a43562468b5e49488ace9b1d6df4abc22022-12-22T03:35:55ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242016-09-0116121591217610.5194/acp-16-12159-2016Future Arctic ozone recovery: the importance of chemistry and dynamicsE. M. Bednarz0A. C. Maycock1A. C. Maycock2A. C. Maycock3N. L. Abraham4N. L. Abraham5P. Braesicke6P. Braesicke7P. Braesicke8O. Dessens9J. A. Pyle10J. A. Pyle11Department of Chemistry, University of Cambridge, Cambridge, UKDepartment of Chemistry, University of Cambridge, Cambridge, UKNational Centre for Atmospheric Science – Climate, University of Cambridge, Cambridge, UKnow at: School of Earth and Environment, University of Leeds, Leeds, UKDepartment of Chemistry, University of Cambridge, Cambridge, UKNational Centre for Atmospheric Science – Climate, University of Cambridge, Cambridge, UKDepartment of Chemistry, University of Cambridge, Cambridge, UKNational Centre for Atmospheric Science – Climate, University of Cambridge, Cambridge, UKnow at: Karlsruhe Institute of Technology, Institute for Meteorology and Climate Research, Karlsruhe, GermanyUniversity College London, London, UKDepartment of Chemistry, University of Cambridge, Cambridge, UKNational Centre for Atmospheric Science – Climate, University of Cambridge, Cambridge, UKFuture trends in Arctic springtime total column ozone, and its chemical and dynamical drivers, are assessed using a seven-member ensemble from the Met Office Unified Model with United Kingdom Chemistry and Aerosols (UM-UKCA) simulating the period 1960–2100. The Arctic mean March total column ozone increases throughout the 21st century at a rate of ∼ 11.5 DU decade<sup>−1</sup>, and is projected to return to the 1980 level in the late 2030s. However, the integrations show that even past 2060 springtime Arctic ozone can episodically drop by ∼ 50–100 DU below the corresponding long-term ensemble mean for that period, reaching values characteristic of the near-present-day average level. Consistent with the global decline in inorganic chlorine (Cl<sub><i>y</i></sub>) over the century, the estimated mean halogen-induced chemical ozone loss in the Arctic lower atmosphere in spring decreases by around a factor of 2 between the periods 2001–2020 and 2061–2080. However, in the presence of a cold and strong polar vortex, elevated halogen-induced ozone losses well above the corresponding long-term mean continue to occur in the simulations into the second part of the century. The ensemble shows a significant cooling trend in the Arctic winter mid- and upper stratosphere, but there is less confidence in the projected temperature trends in the lower stratosphere (100–50 hPa). This is partly due to an increase in downwelling over the Arctic polar cap in winter, which increases transport of ozone into the polar region as well as drives adiabatic warming that partly offsets the radiatively driven stratospheric cooling. However, individual winters characterised by significantly suppressed downwelling, reduced transport and anomalously low temperatures continue to occur in the future. We conclude that, despite the projected long-term recovery of Arctic ozone, the large interannual dynamical variability is expected to continue in the future, thereby facilitating episodic reductions in springtime ozone columns. Whilst our results suggest that the relative role of dynamical processes for determining Arctic springtime ozone will increase in the future, halogen chemistry will remain a smaller but non-negligible contributor for many decades to come.https://www.atmos-chem-phys.net/16/12159/2016/acp-16-12159-2016.pdf |
| spellingShingle | E. M. Bednarz A. C. Maycock A. C. Maycock A. C. Maycock N. L. Abraham N. L. Abraham P. Braesicke P. Braesicke P. Braesicke O. Dessens J. A. Pyle J. A. Pyle Future Arctic ozone recovery: the importance of chemistry and dynamics Atmospheric Chemistry and Physics |
| title | Future Arctic ozone recovery: the importance of chemistry and dynamics |
| title_full | Future Arctic ozone recovery: the importance of chemistry and dynamics |
| title_fullStr | Future Arctic ozone recovery: the importance of chemistry and dynamics |
| title_full_unstemmed | Future Arctic ozone recovery: the importance of chemistry and dynamics |
| title_short | Future Arctic ozone recovery: the importance of chemistry and dynamics |
| title_sort | future arctic ozone recovery the importance of chemistry and dynamics |
| url | https://www.atmos-chem-phys.net/16/12159/2016/acp-16-12159-2016.pdf |
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