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| Titel |
Variability of the total ozone trend over Europe for the period 1950-2004 derived from reconstructed data |
| VerfasserIn |
J. W. Krzyścin, J. L. Borkowski |
| 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 ; 8, no. 11 ; Nr. 8, no. 11 (2008-06-04), S.2847-2857 |
| Datensatznummer |
250006178
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| Publikation (Nr.) |
 copernicus.org/acp-8-2847-2008.pdf |
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| Zusammenfassung |
| The total ozone data over Europe are available for only few ground-based
stations in the pre-satellite era disallowing examination of the spatial
trend variability over the whole continent. A need of having gridded ozone
data for a trend analysis and input to radiative transfer models stimulated
a reconstruction of the daily ozone values since January 1950. Description
of the reconstruction model and its validation were a subject of our
previous paper. The data base used was built within the objectives of the
COST action 726 "Long-term changes and climatology of UV radiation over
Europe". Here we focus on trend analyses. The long-term variability of
total ozone is discussed using results of a flexible trend model applied to
the reconstructed total ozone data for the period 1950–2004. The trend
pattern, which comprises both anthropogenic and "natural" component, is
not a priori assumed but it comes from a smooth curve fit to the zonal
monthly means and monthly grid values. The ozone long-term changes are
calculated separately for cold (October–next year April) and warm
(May–September) seasons. The confidence intervals for the estimated ozone
changes are derived by the block bootstrapping. The statistically
significant negative trends are found almost over the whole Europe only in
the period 1985–1994. Negative trends up to −3% per decade appeared over
small areas in earlier periods when the anthropogenic forcing on the ozone
layer was weak . The statistically positive trends are found only during
warm seasons 1995–2004 over Svalbard archipelago. The reduction of ozone
level in 2004 relative to that before the satellite era is not dramatic,
i.e., up to ~−5% and ~−3.5% in the cold and warm
subperiod, respectively. Present ozone level is still depleted over many
popular resorts in southern Europe and northern Africa. For high latitude
regions the trend overturning could be inferred in last decade (1995–2004)
as the ozone depleted areas are not found there in 2004 in spite of
substantial ozone depletion in the period 1985–1994. |
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