Circulation of the Glacial Atlantic: ASynthesis of Global and Regional Modeling

In recent years, a great wealth of new glacial sea-surface temperatures and salinities have been reconstructed from sediment core data for the intermediate to high latitudes of the North Atlantic. In the present study, the most recent sea-surface temperature and salinity data from the North Atlantic Ocean have been compiled to develop a physically consistent three-dimensional oceanographic scenario of circulation at the Last Glacial Maximum. For a hierarchy of numerical experiments, two general ocean circulation models, driven by traditional restoring boundary conditions, have been used. For the global experiments, a descendant of the Hamburg Large-Scale Geostrophic (LSG) ocean model has been employed, and regional experiments have been carried out with the Geophysical Fluid Dynamics Laboratory (GFDL) Modular Ocean Model (MOM). Both models are linked via the output of the global model, which is used for three-dimensional temperature and salinity restoring along the artificial boundaries of the regional model. This coupling of two models with coarse and fine resolutions offers a unique opportunity to exploit both basin-wide sediment core data coverage as well as the high spatial resolution provided by the cores from high northern latitudes.