The interannual variability of the surface eddy kinetic energy

The variability of the surface eddy kinetic energy (EKE) in the Labrador Sea is investigated with a suite of numerical integrations using a regional ocean model. Simulations are performed over the period 1980-2001 and are compared to satellite observations over the last 9 years. The surface EKE pattern in the basin is dominated by a region along the West coast of Green-land where eddies, mainly anticyclonic, are formed by instability of the main currents flowing over the continental slope, consistent with previous ideal-ized results. Here the interannual changes are linked to the shear of the incoming boundary current system imposed as boundary condition to the model domain. The highly variable strength of the East Greenland current at the northeast boundary, derived from the Simple Ocean Data Assimilation (SODA) reanalysis, strongly influences the vortex formation. In the center of the Labrador Sea, where deep convection occurs, a statis-tically significant portion of the modeled interannual surface EKE variability is correlated with the local atmospheric forcing, and both heat and wind fluxes play an important role and can be adopted as predictors at a lag of two-three months. The Arctic Oscillation index can also be used as a remote indicator of the atmospheric fluxes, but with lower skill than local measure-ments. In contrast the North Atlantic Oscillation index does not correlate significantly with the surface EKE at intraseasonal and interannual scales. The analysis of altimeter data over the 1993-2001 supports the existence of this asymmetry between the regime locally forced by the atmosphere in Preprint submitted to Progress in Oceanography January 25, 2011 the central basin, and the regime remotely forced by the incoming bound-ary current along the west Greenland coast. Those results have important implications for monitoring and predicting the surface eddy kinetic energy variability in the Labrador Sea. Keywords