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| Titel |
Three-dimensional model study of the Arctic ozone loss in 2002/2003 and comparison with 1999/2000 and 2003/2004 |
| VerfasserIn |
W. Feng, M. P. Chipperfield, S. Davies, B. Sen, G. Toon, J. F. Blavier, C. R. Webster, C. M. Volk, A. Ulanovsky, F. Ravegnani, P. Gathen, H. Jost, E. C. Richard, H. Claude |
| 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 ; 5, no. 1 ; Nr. 5, no. 1 (2005-01-21), S.139-152 |
| Datensatznummer |
250002213
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| Publikation (Nr.) |
 copernicus.org/acp-5-139-2005.pdf |
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| Zusammenfassung |
| We have used the SLIMCAT 3-D off-line chemical transport model
(CTM) to quantify the Arctic chemical ozone loss in the year
2002/2003 and compare it with similar calculations for the winters 1999/2000
and 2003/2004. Recent changes to the CTM have improved the
model's ability to reproduce polar chemical and dynamical processes.
The updated CTM uses σ-θ as a vertical coordinate which
allows it to extend down to the surface. The CTM
has a detailed stratospheric chemistry scheme and now includes a
simple NAT-based denitrification scheme in the stratosphere.
In the model runs presented here the model was forced by ECMWF ERA40
and operational analyses. The model used 24 levels extending from
the surface to ~55km and a horizontal resolution of either
7.5° x 7.5° or 2.8° x 2.8°.
Two different radiation schemes, MIDRAD and the CCM scheme, were used
to diagnose the vertical motion in the stratosphere. Based
on tracer observations from balloons and aircraft, the more sophisticated
CCM scheme gives a better representation of the vertical transport in
this model which includes the troposphere. The higher resolution model
generally produces larger chemical O3 depletion, which agrees
better with observations.
The CTM results show that very early chemical ozone loss occurred in
December 2002 due to extremely low temperatures and early chlorine activation
in the lower stratosphere. Thus, chemical loss in this winter started earlier
than in the other two winters studied here.
In 2002/2003 the local polar ozone loss in the lower stratosphere
was ~40% before the stratospheric final warming.
Larger ozone loss occurred in the cold year 1999/2000 which had
a persistently cold and stable vortex during most of the winter.
For this winter the
current model, at a resolution of 2.8° x 2.8°, can
reproduce the observed loss of over 70% locally.
In the warm and more disturbed winter 2003/2004 the chemical
O3 loss was generally much smaller, except above
620K where large losses occurred due to a period of very low minimum
temperatures at these altitudes. |
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