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| Titel |
Investigation of polar ozone anomalies with a Chemistry Transport Model: The role of stratospheric dynamics and heterogeneous chemistry |
| VerfasserIn |
Gregor Kiesewetter, Björn-Martin Sinnhuber, Marco Vountas, Mark Weber, John P. Burrows |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250039625
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| Zusammenfassung |
| We introduce a 29-year dataset of stratospheric ozone which has been created from sequential
assimilation of Solar Backscatter UV (SBUV) satellite ozone profile observations into a
chemistry transport model (CTM). Our assimilated dataset shows excellent agreement
with ozone profile data from independent observations (satellite instruments and
sondes), including during polar night when no SBUV observations are available. The
dataset can thus be viewed as a consistent long-term dataset closing the gaps in
satellite observations in order to investigate high-latitude ozone variability. We
use the assimilated dataset to analyze the development and persistence of ozone
anomalies in the Arctic stratosphere, and their relation to stratospheric dynamics.
Ozone anomalies typically develop in the 1000K potential temperature (~ 35 km)
region and slowly descend from there, showing an unexpectedly high persistence of
up to seven months. Anomalies in the stratospheric circulation, expressed by the
Northern Hemisphere Annular Mode (NAM) index, are shown to have a large influence
on ozone anomalies. Extreme phases of the NAM index (strong and weak vortex
events) lead to the creation of distinctively shaped ozone anomalies, which first
appear in the uppermost stratosphere and then rapidly cover the upper and middle
stratosphere, from where they then slowly descend into the lowermost stratosphere
within five months. Using the CTM, we further quantify the role of heterogeneous
chemistry for polar ozone anomalies, and its impact on mid-latitude ozone trends. |
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