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| Titel |
Middle Miocene climate and vegetation modelling with PLASIM and CARAIB |
| VerfasserIn |
A.-J. Henrot, L. François, G. Munhoven, Eric Favre, M. Butzin |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250023793
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| Zusammenfassung |
| In a long-term climatic cooling trend, the Middle Miocene represents one of the last warm
periods of the Neogene, culminating with the Miocene Climatic Optimum, MCO (17-15 My).
Palynological studies suggest that the warmer climatic conditions prevailing during the MCO
allowed warm forests to expand poleward of the subtropical zone, with evergreen forests
proliferating in North America and Europe (Jimenez-Moreno and Suc, 2007, Palaeogeogr.
Palaeoclimatol. Palaeoecol. 253: 208-225).
In this work, we used the Planet Simulator (Fraedrich et al., 2005, Meteorol. Z. 14:
299-304 and 305-314), an Earth system model of intermediate complexity, to carry out
several simulation experiments, where we have assessed the effects of the absence of ice on
the continents, the opening of the Central American and Eastern Tethys seaways, the
lowering of the topography on land and the effect of various atmospheric CO2
concentrations, in agreement with the values reported in the litterature. We then produced
several vegetation distributions, using the dynamic vegetation model CARAIB (Galy
et al., 2008, Quat. Sci. Rev. 27: 1396-1409), to analyse if the climatic forcings
considered are sufficient to explain the expansion of warmer forest types to higher
latitudes.
Our results indicate that an increase of atmospheric CO2 concentration, higher than the
present-day one, is necessary to allow subtropical forest types to expand poleward. This result
agrees wih recent paleo-atmospheric CO2 reconstruction from stomatal frequency analysis,
which suggests 500 ppmv of CO2 during the MCO. However, the required warming may be
due to processes not considered in our setup (e.g. full oceanic circulation or other greenhouse
gases). |
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