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

Reconstructions of the sea surface temperature and salinity of the Med iterranean Sea during the last glacial maximum (LGM) suggest that extr emely cold winters occurred in the western basin and the Aegean, with highly saline conditions in the eastern basin. It is shown here that f orcing the LGM Mediterranean Sea with a representative paleoclimate mo del 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 simila r changes to these reconstructions, being 3 degrees-4 degrees C colder than present day. Another major difference between the LGM and contro l simulations is the location and spreading of subsurface wafer. The w estern basin suffers complete loss of stability in the LGM winter, lea ding to this basin becoming the source for the LGM deep water of the e astern basin. The ocean general circulation model results are shown to be qualitatively consistent with cooler, drier climate along the nort hern coast of the Mediterranean but not with higher surface salinity, thus refining existing paleoclimate reconstructions in the Mediterrane an region.