Last glacial and meltwater interbasin water exchanges and sedimentation in the world ocean

Abstract

Modeling the global ocean thermohaline conveyor at present, at the Last Glacial Maximum, and at a subsequent meltwater event is revisited using a combination of an ocean global circulation model and a sediment transport model. The modeled changes of sediment deposition rates, linked to the changes of the global deep-ocean thermohaline circulation, provide a better understanding of the glacial-to-interglacial variability of thermohaline currents, and help to identify the regions of the world ocean that are most sensitive to the glacial and meltwater impacts. In addition to the well-known local changes of the conveyor in the Atlantic Ocean during the last glaciation and subsequent meltwater events, the simulations show the global character of these impacts, detected as far from the North Atlantic as the Indian and the southwestern Pacific Oceans. However, the numerical experiments challenge the idea of a global conveyor-like deep flow strongly connecting the surface waters of northern parts of the North Atlantic and North Pacific Oceans at either glacial or meltwater intervals.