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| Titel |
The influence of ocean gateways on climate: Numerical sensitivity studies on ocean circulation rearrangements |
| VerfasserIn |
C. Stepanek, G. Lohmann, 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 |
250030683
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| Zusammenfassung |
| Climate transitions may be triggered by tectonic changes of ocean gateways causing the
reorganisation of the global ocean circulation. During the last 50 million years major tectonic
changes occurred. The opening of Drake Passage and Tasman Passage (around 40 Ma before
present) and the closure of the Isthmus of Panama (around 3 Ma ago) are thought to
be a reason for major Cenozoic climate changes, but the actual climate impact of
these events is not yet clear, as other driving mechanisms have to be considered as
well.
Here, we present model results of advective oceanic heat transport changes which were
obtained in idealised numerical experiments employing a global ocean general
circulation model coupled with a simple atmospheric energy balance model. Using
present-day forcing, we investigated the effects of various historical ocean gateway
configurations.
Our preliminary results support the hypothesis that oceanic heat transport is sensitive to
tectonic gateway forcing. Significant changes in ocean circulation patterns and
temperatures are visible. Compared to the present-day simulation, a gateway configuration
characteristic of 40 Ma ago (Drake Passage closed, Panama Strait opened, Tethys
opened) reduces the maximum northward oceanic heat transport by more than 50
percent, while the maximum southward oceanic heat transport more than triples. Other
gateway configurations lead to meridional heat transports in between these two
experiments.
Using an ocean carbon cycle circulation model we also study the distribution of marine
δ13C associated with the ocean circulation changes, and interprete the outcomes with respect
to the paleoclimatic record. |
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