North Atlantic Current in model and observations: Transport variability, flow paths and hydrography

The North Atlantic Current (NAC) is subject to variability on multiannual to decadal time scales, influencing the transport of volume, heat and freshwater from the subtropical to the eastern subpolar North Atlantic (NA). Current observational time series are either too short or too episodic to comprehensively study the processes involved, therefore models are used to complement the observations. For this study, moored and ship-based observations from three sections along the NAC pathway, satellite altimetry data and 1/20 degree hindcast VIKING20 model configuration (1960-2008) output are used. They are investigated and compared to describe hydrography, flow field and transport time series. The flow into and out of the NA is monitored at 47 degree N, the flow from the western into the eastern basin of the NA is captured by a section at the western flank of the Mid-Atlantic Ridge (MAR), and the distribution in the eastern basin of the NA is observed at the OVIDE line. These three sections thus provide an extensive picture of the flow.