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| Titel |
Chemical contribution to future tropical ozone change in the lower stratosphere |
| VerfasserIn |
S. Meul, U. Langematz, S. Oberländer, H. Garny, P. Jöckel |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 14, no. 6 ; Nr. 14, no. 6 (2014-03-25), S.2959-2971 |
| Datensatznummer |
250118521
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| Publikation (Nr.) |
 copernicus.org/acp-14-2959-2014.pdf |
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| Zusammenfassung |
| The future evolution of tropical ozone in a changing climate is investigated
by analysing time slice simulations made with the chemistry–climate model
EMAC. Between the present and the end of the 21st century a significant
increase in ozone is found globally for the upper stratosphere and the
extratropical lower stratosphere, while in the tropical lower stratosphere
ozone decreases significantly by up to 30%. Previous studies have shown
that this decrease is connected to changes in tropical upwelling. Here the
dominant role of transport for the future ozone decrease is confirmed, but it
is found that in addition changes in chemical ozone production and
destruction do contribute to the ozone changes in the tropical lower
stratosphere. Between 50 and 30 hPa the dynamically induced ozone decrease of
up to 22% is amplified by 11–19% due to a reduced ozone production. This
is counteracted by a decrease in the ozone loss causing an ozone increase by
15–28%. At 70 hPa the large ozone decrease due to transport (−52%) is
reduced by an enhanced photochemical ozone production (+28%) but slightly
increased (−5%) due to an enhanced ozone loss. It is found that the
increase in the ozone production in the lowermost stratosphere is mainly due
to a transport induced decrease in the overlying ozone column while at higher
altitudes the ozone production decreases as a consequence of a chemically
induced increase in the overlying ozone column. The ozone increase that is
attributed to changes in ozone loss between 50 and 30 hPa is mainly caused by
a slowing of the ClOx and NOx loss cycles. The enhanced ozone
destruction below 70 hPa can be attributed to an increased efficiency of the
HOx loss cycle. The role of ozone transport in determining the ozone trend
in this region is found to depend on the changes in the net production as a
reduced net production also reduces the amount of ozone that can be
transported within an air parcel. |
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