The 1992-2009 transport variability of the East Greenland-Irminger Current at 60N

Abstract

The East Greenland Irminger Current (EGIC) decadal transport variability likely influences deep convection intensity in the Labrador and Irminger Seas but is poorly known yet. The EGIC transport west of the 2000 m isobath was estimated, for the first time, between 1992 and 2009 by combining surface geostrophic velocities derived from altimetry with an estimate of the vertical structure of the transport variability statistically determined from a moored array deployed in 2004-2006. The reconstructed 17-year time series of the EGIC transport was then validated against independent estimates confirming that, indeed, the vertical distribution of the EGIC variability has not changed significantly over the last two decades. The 1992-2009 mean transport is 19.5 Sv with a standard error of 0.3 Sv (1 Sv = 10 6 m 3 s -1). In 1992-1996, the EGIC transport was close to the average. Over the following decade (1997-2005), the EGIC transport declined by 3 Sv (15%) so that the 2004-2006 mean transport inferred from the moored array is 2.2 Sv (10%) less than the 1992-2009 mean. It was followed by a period of higher transport. The seasonal to interannual transport variability is coherent with the variability of the windstress curl at the center of the Irminger Sea. Copyright 2011 by the American Geophysical Union.