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| Titel |
Simulation of the climate impact of Mt. Pinatubo eruption using ECHAM5 – Part 1: Sensitivity to the modes of atmospheric circulation and boundary conditions |
| VerfasserIn |
M. A. Thomas, C. Timmreck, M. A. Giorgetta, H.-F. Graf, G. Stenchikov |
| 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 ; 9, no. 2 ; Nr. 9, no. 2 (2009-01-29), S.757-769 |
| Datensatznummer |
250006755
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| Publikation (Nr.) |
 copernicus.org/acp-9-757-2009.pdf |
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| Zusammenfassung |
| The eruption of Mt. Pinatubo in the Philippines in June 1991 was one of the
strongest volcanic eruptions in the 20th century and this well observed
eruption can serve as an important case study to understand the subsequent
weather and climate changes. In this paper, the most comprehensive
simulations to date of the climate impact of Mt. Pinatubo eruption are
carried out with prescribed volcanic aerosols including observed SSTs, QBO
and volcanically induced ozone anomalies. This is also the first attempt to
include all the known factors for the simulation of such an experiment. Here,
the climate response is evaluated under different boundary conditions
including one at a time, thereby, investigating the radiative and dynamical
responses to individual and combined forcings by observed SSTs, QBO and
volcanic effects. Two ensembles of ten members each, for unperturbed and
volcanically perturbed conditions were carried out using the middle
atmosphere configuration of ECHAM5 general circulation model. Our results
show that the simulated climate response that may arise solely from aerosol
forcing in lower stratospheric temperature is insensitive to the boundary
conditions in the tropics and does not show some observed features such as
the temperature signature of the QBO phases. Also, statistically significant
positive anomalies in the high latitudes in NH winter of 1991/92 seen in our
model simulations with prescribed observed SST and QBO phases as boundary
conditions are consistent with the observations. To simulate realistically
the lower stratospheric temperature response, one must include all the known
factors. The pure QBO and ocean signatures in lower stratospheric temperature
are simulated consistently with earlier studies. The indirect effect of the
volcanic aerosols manifested as the winter warming pattern is not simulated
in the ensemble mean of the experiments. Our analysis also shows that the
response to El Niño conditions is very strong in the model and
that it partially masks the effects due to volcanic forcing. |
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