Investigation of Labrador Sea Dynamics with the High-Resolution Finite Element Sea Ice - Ocean Model FESOM

The subpolar regions of the North Atlantic ocean are crucial for the global climate in terms of deep water formation, which is a major driver for the Atlantic Meridional Overturning Circulation (AMOC) that transports heat into northern latitudes and returns cold deep water masses southward. Through air-sea buoyancy fluxes and resulting vertical ventilation a homogenized deep mixing layer evolves, and the so called Labrador Sea Water (LSW) is formed. LSW is the upper component of the North Atlantic Deep Water (NADW) and an important constituent of the cold limb of the AMOC (e.g. Rhein et al. 2011).
In order to preserve the ocean-atmosphere heat budget it is assumed that meso-scale eddies transport heat from the boundary currents into the interior of the Labrador Sea (Lilly et al. 2003, Spall 2004, Chanut et al. 2008, Saenko et al. 2014).

With the global Finite-Element Sea-Ice Ocean Model (FESOM) on an unstructured mesh and a horizontal resolution of 5 km in the North Atlantic Gyre the formation and variability of different classes of Labrador Sea mode waters including deep water formation are investigated from 1948 until 2015. We further analyze eddy effects on the horizontal mixing between the Labrador Sea Boundary Current System and the central Labrador Sea and the induced lateral fluxes of heat and freshwater into the open ocean (e.g. Rhein et al. 2015) by comparing modeling and observational data.