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| Titel |
A model intercomparison analysing the link between column ozone and geopotential height anomalies in January |
| VerfasserIn |
P. Braesicke, C. Brühl, M. Dameris, R. Deckert, V. Eyring, M. A. Giorgetta, E. Mancini, E. Manzini, G. Pitari, J. A. Pyle, B. Steil |
| 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. 9 ; Nr. 8, no. 9 (2008-05-09), S.2519-2535 |
| Datensatznummer |
250006106
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| Publikation (Nr.) |
 copernicus.org/acp-8-2519-2008.pdf |
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| Zusammenfassung |
| A statistical framework to evaluate the performance of chemistry-climate
models with respect to the interaction between meteorology and column
ozone during northern hemisphere mid-winter, in particularly January, is used.
Different statistical diagnostics from four chemistry-climate models (E39C, ME4C,
UMUCAM, ULAQ) are compared with the ERA-40 re-analysis. First, we analyse
vertical coherence in geopotential height anomalies as described by linear
correlations between two different pressure levels (30 and 200 hPa) of the
atmosphere. In addition, linear correlations between column ozone
and geopotential height anomalies at 200 hPa are discussed to motivate a
simple picture of the meteorological impacts on column ozone on interannual
timescales. Secondly, we discuss characteristic spatial structures in
geopotential height and column ozone anomalies as given by their
first two empirical orthogonal functions. Finally, we describe the covariance
patterns between reconstructed anomalies of geopotential height and
column ozone. In general we find good agreement between the models with
higher horizontal resolution (E39C, ME4C, UMUCAM) and ERA-40.
The Pacific-North American (PNA) pattern emerges as a useful qualitative
benchmark for the model performance. Models with higher horizontal resolution
and high upper boundary (ME4C and UMUCAM) show good agreement with the PNA tripole
derived from ERA-40 data, including the column ozone modulation over the Pacfic
sector. The model with lowest horizontal resolution does not show a classic PNA
pattern (ULAQ), and the model with the lowest upper boundary (E39C) does not
capture the PNA related column ozone variations over the Pacific sector.
Those discrepancies have to be taken into account when providing confidence
intervals for climate change integrations. |
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