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| Titel |
Intercomparison between Lagrangian and Eulerian simulations of the development of mid-latitude streamers as observed by CRISTA |
| VerfasserIn |
F. Khosrawi, J.-U. Grooß, R. Müller, P. Konopka, W. Kouker, R. Ruhnke, T. Reddmann, M. Riese |
| 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 (2005-01-20), S.85-95 |
| Datensatznummer |
250002209
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| Publikation (Nr.) |
 copernicus.org/acp-5-85-2005.pdf |
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| Zusammenfassung |
| During the CRISTA-1 mission three pronounced fingerlike structures reaching
from the lower latitudes to the mid-latitudes, so-called streamers, were
observed in the measurements of several trace gases in early November 1994. A
simulation of these streamers in previous studies employing the KASIMA
(Karlsruhe Simulation Model of the Middle Atmosphere) and ROSE (Research on
Ozone in the Stratosphere and its Evolution) model, both being Eulerian
models, show that their formation is due to adiabatic transport processes.
Here, the impact of mixing on the development of these streamers is
investigated. These streamers were simulated with the CLaMS model (Chemical
Lagrangian Model of the Stratosphere), a Lagrangian model, using N2O as
long-lived tracer. Using several different initialisations the results were
compared to the KASIMA simulations and CRISTA (Cryogenic Infrared
Spectrometer and Telescope for the Atmosphere) observations. Further, since
the KASIMA model was employed to derive a 9-year climatology, the quality of
the reproduction of streamers from such a study was tested by the comparison
of the KASIMA results with CLaMS and CRISTA. The streamers are reproduced
well for the Northern Hemisphere in the simulations of CLaMS and KASIMA for
the 6 November 1994. However, in the CLaMS simulation a stronger
filamentation is found while larger discrepancies between KASIMA and CRISTA
were found especially for the Southern Hemisphere. Further, compared to the
CRISTA observations the mixing ratios of N2O are in general underestimated
in the KASIMA simulations. An improvement of the simulations with KASIMA was
obtained for a simulation time according to the length of the CLaMS
simulation. To quantify the differences between the simulations with CLaMS
and KASIMA, and the CRISTA observations, the probability density function
technique (PDF) is used to interpret the tracer distributions. While in the
PDF of the KASIMA simulation the small scale structures observed by CRISTA
are smoothed out due to the numerical diffusion in the model, the PDFs
derived from CRISTA observations can be reproduced by CLaMS by optimising the
mixing parameterisation. Further, this procedure gives information on
small-scale variabilities not resolved by the CRISTA observations. |
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