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abstracts
Modelling changes in eastern Mediterranean ocean climate for the early Holocene
Fanny Adloff, Uwe Mikolajewicz
During the early Holocene, the Mediterranean circulation has undergone big changes. Those changes are reflected in the occurrence of organic-rich marine sediments called sapropels in the eastern Mediterranean, which indicate the presence of oxygen depleted deep waters. A possible explanation is that a precession-induced increase in the amount of freshwater input leads to a reduction of the deep water ventilation and could allow the formation of those organic layers.
The relative isolation of the basin together with a good coverage of available proxy data make this region an ideal testbed for modelling past climate changes. The work presented here is a first step towards elucidating the mechanisms responsible for sapropels formation.
We set up a regional version of the general ocean circulation model MPIOM for the Mediterranean. We force the model with atmospheric data derived from equilibrium time slice simulations with the coupled atmosphere/ocean/dynamical vegetation model ECHAM5/MPIOM/LPJ. We focus on the 9 ka BP time slice (500 years integration).
The effect of insolation and fresh water input changes on Mediterranean ocean climate are analyzed. The amplitude of the SST seasonal cycle is stronger, leading to colder winters with a resulting cooling of the deeper layers. The enhanced summer warming is restricted to the very uppermost layers leading to a strong temperature gradient. The enhanced Nile runoff is overcompensated by the missing outflow from the Bosporus. The location of Aegean deep water formation is shifted westward. The model results are compared to available paleoproxy data.
Fanny Adloff, The Ocean in the Earth System, Max Planck Institute for Meteorology,Bundesstrasse 53, 20146 Hamburg, Germany, fanny.adloff@zmaw.de
Uwe Mikolajewicz, Max Planck Institute for Meteorology, The Ocean in the Earth System, Hamburg, 20146, Germany
Session: CCT3: Modeling
Download Poster:
> Adloff_OSM.pdf
Download Talk:
> YSM09_OralE_Adloff.pdf
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