AN OCEAN GENERAL-CIRCULATION MODEL VIEW OF THE GLACIAL MEDITERRANEAN THERMOHALINE CIRCULATION

Reconstructions of the sea surface temperature and salinity of the Mediterranean Sea during the last glacial maximum (LGM) suggest that extremely cold winters occurred in the western basin and the Aegean, with highly saline conditions in the eastern basin. It is shown here that forcing the LGM Mediterranean Sea with a representative paleoclimate model results in significantly less extreme salinity conditions than are suggested by existing reconstructions. Modeled sea surface salinities are, at most, 0.1-0.2 parts per thousand higher than today at the LGM, rather than the previously suggested 2-3 parts per thousand. Modeled sea surface temperatures over the western basin, however, show similar changes to these reconstructions, being 3 degrees-4 degrees C colder than present day. Another major difference between the LGM and control simulations is the location and spreading of subsurface wafer. The western basin suffers complete loss of stability in the LGM winter, leading to this basin becoming the source for the LGM deep water of the eastern basin. The ocean general circulation model results are shown to be qualitatively consistent with cooler, drier climate along the northern coast of the Mediterranean but not with higher surface salinity, thus refining existing paleoclimate reconstructions in the Mediterranean region.