MODELING SEDIMENT DRIFTS - A COUPLED OCEANIC CIRCULATION-SEDIMENTATION MODEL OF THE NORTHERN NORTH-ATLANTIC

Modeling of sediment drifts in the northern North Atlantic is achieved by coupling the ocean general circulation model sensitivity and circu lation in the northern North Atlantic (SCINNA) to the sedimentation mo dels sedimentation in the northern North Atlantic (SENNA) and particle tracing in the northern North Atlantic (PATRINNA). SCINNA is based on the primitive equations with conservation of mass, momentum, heat, an d salt. SENNA and PATRINNA are driven by temperature, salinity, and ve locity fields derived from SCINNA. Sediments are supplied from the sur face and from the continental margins. The modeling includes three-dim ensional sediment transport in the water column and two-dimensional pr ocesses in a thin bottom layer. Sediments are allowed to resuspend rep eatedly, thus offering the possibility of stepwise transport. SENNA ca lculates erosion, transport, and deposition of sediments, resulting in sedimentation patterns for specific time intervals. PATRINNA models t he transport paths of single sediment grains corresponding to the ocea n circulation. Sensitivity experiments for the modern state and for th e last glacial maximum show differences in the large sediment; drifts between the Charlie Gibbs Fracture Zone and the Greenland-Scotland Rid ge for these two time slices. The sediment supply changes with the dif fering circulation modes and is strongly constrained by topography.