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| Titel |
Record-breaking ozone loss in the Arctic winter 2010/2011: comparison with 1996/1997 |
| VerfasserIn |
J. Kuttippurath, S. Godin-Beekmann, F. Lefèvre, G. Nikulin, M. L. Santee, L. Froidevaux |
| 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 ; 12, no. 15 ; Nr. 12, no. 15 (2012-08-06), S.7073-7085 |
| Datensatznummer |
250011371
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| Publikation (Nr.) |
 copernicus.org/acp-12-7073-2012.pdf |
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| Zusammenfassung |
| We present a detailed discussion of the chemical and dynamical processes in
the Arctic winters 1996/1997 and 2010/2011 with high resolution chemical
transport model (CTM) simulations and space-based observations. In the Arctic
winter 2010/2011, the lower stratospheric minimum temperatures were below
195 K for a record period of time, from December to mid-April, and a strong
and stable vortex was present during that period. Simulations with the
Mimosa-Chim CTM show that the chemical ozone loss started in early January
and progressed slowly to 1 ppmv (parts per million by volume) by late
February. The loss intensified by early March and reached a record maximum of
~2.4 ppmv in the late March–early April period over a broad altitude
range of 450–550 K. This coincides with elevated ozone loss rates of
2–4 ppbv sh−1 (parts per billion by volume/sunlit hour) and a
contribution of about 30–55% and 30–35% from the ClO-ClO and
ClO-BrO cycles, respectively, in late February and March. In addition, a
contribution of 30–50% from the HOx cycle is also estimated
in April. We also estimate a loss of about 0.7–1.2 ppmv contributed
(75%) by the NOx cycle at 550–700 K. The ozone loss
estimated in the partial column range of 350–550 K exhibits a record value
of ~148 DU (Dobson Unit). This is the largest ozone loss ever estimated
in the Arctic and is consistent with the remarkable chlorine activation and
strong denitrification (40–50%) during the winter, as the modeled ClO
shows ~1.8 ppbv in early January and ~1 ppbv in March at
450–550 K. These model results are in excellent agreement with those found
from the Aura Microwave Limb Sounder observations. Our analyses also show
that the ozone loss in 2010/2011 is close to that found in some Antarctic
winters, for the first time in the observed history. Though the winter
1996/1997 was also very cold in March–April, the temperatures were higher in
December–February, and, therefore, chlorine activation was moderate and
ozone loss was average with about 1.2 ppmv at 475–550 K or 42 DU at
350–550 K, as diagnosed from the model simulations and measurements. |
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