 |
| Titel |
Variability and trends in total and vertically resolved stratospheric ozone based on the CATO ozone data set |
| VerfasserIn |
D. Brunner, J. Staehelin, J. A. Maeder, I. Wohltmann, G. E. Bodeker |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1680-7316
|
| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 6, no. 12 ; Nr. 6, no. 12 (2006-10-31), S.4985-5008 |
| Datensatznummer |
250004165
|
| Publikation (Nr.) |
 copernicus.org/acp-6-4985-2006.pdf |
|
|
|
|
|
| Zusammenfassung |
| Trends in ozone columns and vertical distributions were calculated
for the period 1979–2004 based on the ozone data set CATO
(Candidoz Assimilated Three-dimensional Ozone) using a multiple
linear regression model. CATO has been reconstructed from TOMS,
GOME and SBUV total column ozone observations in an equivalent
latitude and potential temperature framework and offers a pole to
pole coverage of the stratosphere on 15 potential temperature
levels. The regression model includes explanatory variables
describing the influence of the quasi-biennial oscillation (QBO),
volcanic eruptions, the solar cycle, the Brewer-Dobson
circulation, Arctic ozone depletion, and the increase in
stratospheric chlorine. The effects of displacements of the polar
vortex and jet streams due to planetary waves, which may
significantly affect trends at a given geographical latitude, are
eliminated in the equivalent latitude framework. The QBO shows a
strong signal throughout most of the lower stratosphere with peak
amplitudes in the tropics of the order of 10–20% (peak to
valley). The eruption of Pinatubo led to annual mean ozone
reductions of 15–25% between the tropopause and 23 km in
northern mid-latitudes and to similar percentage changes in the
southern hemisphere but concentrated at altitudes below 17 km.
Stratospheric ozone is elevated over a broad latitude range by up
to 5% during solar maximum compared to solar minimum, the largest
increase being observed around 30 km. This is at a lower altitude
than reported previously, and no negative signal is found in the
tropical lower stratosphere. The Brewer-Dobson circulation shows a
dominant contribution to interannual variability at both high and
low latitudes and accounts for some of the ozone increase seen in
the northern hemisphere since the mid-1990s. Arctic ozone
depletion significantly affects the high northern latitudes
between January and March and extends its influence to the
mid-latitudes during later months. The vertical distribution of
the ozone trend shows distinct negative trends at about 18 km in
the lower stratosphere with largest declines over the poles, and
above 35 km in the upper stratosphere. A narrow band of large
negative trends extends into the tropical lower stratosphere.
Assuming that the observed negative trend before 1995 continued to
2004 cannot explain the ozone changes since 1996. A model
accounting for recent changes in equivalent effective
stratospheric chlorine, aerosols and Eliassen-Palm flux, on the
other hand, closely tracks ozone changes since 1995. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|