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| Titel |
The Brewer-Dobson circulation and total ozone from seasonal to decadal time scales |
| VerfasserIn |
M. Weber, S. Dikty, J. P. Burrows, H. Garny, M. Dameris, A. Kubin, J. Abalichin, U. Langematz |
| 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 ; 11, no. 21 ; Nr. 11, no. 21 (2011-11-11), S.11221-11235 |
| Datensatznummer |
250010184
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| Publikation (Nr.) |
 copernicus.org/acp-11-11221-2011.pdf |
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| Zusammenfassung |
| The effect of the winter Brewer-Dobson circulation (BDC) on the seasonal
and decadal evolution of total ozone in both hemispheres is investigated
using satellite total ozone data from the merged GOME/SCIAMACHY/GOME-2
(GSG) data set (1995–2010) and outputs from two chemistry-climate models
(CCM), the FUB-EMAC and DLR-E39C-A models. Combining data from both
hemispheres a linear relationship between the winter average
extratropical 100 hPa eddy heat flux and the ozone ratio with respect to
fall ozone levels exists and is statistically significant for tropical
as well as polar ozone. The high correlation at high latitudes persists
well into the summer months until the onset of the next winter season.
The anti-correlation of the cumulative eddy heat flux with tropical
ozone ratios, however, breaks down in spring as the polar vortex erodes
and changes to a weak positive correlation similar to that observed at
high latitudes. The inter-annual variability and decadal evolution of
ozone in each hemisphere in winter, spring, and summer are therefore
driven by the cumulative effect of the previous winter's meridional
circulation. This compact linear relationship is also found in both CCMs
used in this study indicating that current models realistically describe
the variability in stratospheric circulation and its effect on total
ozone. Both models show a positive trend in the winter mean eddy heat
flux (and winter BDC strength) in both hemispheres until year 2050,
however the inter-annual variability (peak-to-peak) is two to three
times larger than the mean change between 1960 and 2050. It is,
nevertheless, possible to detect a shift in this compact linear
relationship related to past and future changes in the stratospheric
halogen load. Using the SBUV/TOMS/OMI (MOD V8) merged data set
(1980–2010), it can be shown that from the decade 1990–1999 to 2000–2010
this linear relationship remained unchanged (before and after the
turnaround in the stratospheric halogen load), while a shift is evident
between 1980–1989 (upward trend in stratospheric halogen) and the 1990s,
which is a clear sign that an onset of recovery is detectable despite
the large variability in polar ozone. Because of the large variability
from year to year in the BDC circulation substantial polar ozone
depletion may still occur in coming decades in selected winters with
weak BDC and very low polar stratospheric temperatures. |
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