Recent changes in the Greenland-Scotland overflow-derived water transport inferred from hydrographic observations in the southern Irminger Sea

Abstract

Recent decadal changes (1955-2007) in the baroclinic transport (T BC) of the Deep Western Boundary Current (DWBC) carrying the Greenland-Scotland overflowderived waters along the East Greenland slope are quantified from a set of hydrographic sections in vicinity of Cape Farewell. The updated historical record of TBC shows clear decadal variability (±2-2.5 Sv) with the transport minima in the 1950s and mid-1990s, maximum in the early 1980s and moderate-to-high transport in the 2000s. Since the mid-1990s, the DWBC TBC has increased by ∼2 Sv (significant at the 99.9% level), which constitute ∼20% of the mean absolute transport (9.0 Sv) as obtained from three cruises in 2002-2006. The DWBC TBC anomalies negatively correlate (R = -0.80) with thickness anomalies of the Labrador Sea Water (LSW) at its origin implying a close association, albeit not necessarily causative, between the DWBC transport east of Greenland and the LSW production. Copyright 2009 by the American Geophysical Union.