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| Titel |
Summertime free-tropospheric ozone pool over the eastern Mediterranean/Middle East |
| VerfasserIn |
P. Zanis, P. Hadjinicolaou, A. Pozzer, E. Tyrlis, S. Dafka, N. Mihalopoulos, J. Lelieveld  |
| 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. 1 ; Nr. 14, no. 1 (2014-01-03), S.115-132 |
| Datensatznummer |
250118246
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| Publikation (Nr.) |
 copernicus.org/acp-14-115-2014.pdf |
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| Zusammenfassung |
| Observations show that the Mediterranean troposphere is characterized by a
marked enhancement in summertime ozone, with a maximum over the eastern
Mediterranean. This has been linked to enhanced photochemical ozone
production and subsidence under cloud-free anticyclonic conditions. The
eastern Mediterranean is among the regions with the highest levels of
background tropospheric ozone worldwide. A 12 yr climatological analysis
(1998–2009) of free-tropospheric ozone was carried out over the region based
on the ECMWF (European Centre for Medium-Range Weather Forecasts)
ERA-Interim reanalysis data and simulations with the EMAC (ECHAM5–MESSy)
atmospheric chemistry–climate model. EMAC is nudged towards the ECMWF
analysis data and includes a stratospheric ozone tracer. A characteristic
summertime pool with high ozone concentrations is found in the middle
troposphere over the eastern Mediterranean–Middle East (EMME) in the
ERA-Interim ozone data, Tropospheric Emission Spectrometer (TES) satellite
ozone data and simulations with EMAC. The enhanced ozone over the EMME
during summer is a robust feature, extending down to lower free-tropospheric
levels. The investigation of ozone in relation to potential vorticity and
water vapour and the stratospheric ozone tracer indicates that the dominant
mechanism causing the free-tropospheric ozone pool is the downward transport
from the upper troposphere and lower stratosphere, in association with the
enhanced subsidence and the limited horizontal divergence observed over the
region. The implications of these high free-tropospheric ozone levels on the
seasonal cycle of near-surface ozone over the Mediterranean are discussed. |
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