Seasonal to interannual variability of the eddy field in the Labrador Sea from satellite altimetry

Sea level anomalies measured by the altimeters aboard the TOPEX/Poseidon and ERS satellites for the periods 1993–2001 and 1997–2001, respectively, are used to investigate the eddy field in the subpolar North Atlantic and in the Labrador Sea. A quadratic correction of the obtained eddy kinetic energy (EKE) with respect to significant wave height is applied that led to an increased correlation between moored and altimetric EKE in the central Labrador Sea. The mean EKE field shows higher levels associated with the main currents and a strong seasonality in the Labrador Sea. The annual cycle of the EKE shows a propagation of West Greenland Current (WGC) EKE into the central Labrador Sea with a mean southward propagation speed of about 3 cm s −1 , while the EKE maximum in the Labrador Current is well separated from the interior by local EKE minima. The interannual variability of the EKE in the Labrador Sea shows distinct regional differences. In the WGC region, strong early winter maxima are found during 1993 and 1997–1999. In the central Labrador Sea, maxima are found during March/April 1993–1995 and 1997. Variations in the annual cycle of the WGC EKE are observed: While there is a weak annual cycle in the WGC region during 1994–1996 with more continuous EKE generation, during 1997–2000, there is a strong seasonal cycle with maximum EKE during January and particularly low EKE during summer. The propagation of WGC EKE into the central Labrador Sea is enhanced during 1997–2000, leading to a long persistence of EKE in the central Labrador Sea. During 1993–1995 and 1997 the central Labrador Sea EKE almost instantaneously increased during March/April, followed, in the earlier years, by a relatively fast destruction of the winterly generated EKE.