Variability of the water mass transports and fluxes in the eastern North Atlantic during 2001

Abstract

The water mass distribution in the eastern North Atlantic Ocean (39–45°N, 16–22°W) during 2001 was determined for the upper 2000 m within the frame of the French research program POMME, using an extended Optimum Multiparameter analysis which included both conservative and nonconservative tracers. The presence of eastern North Atlantic Central Water in its subtropical and subpolar branches, Mediterranean Water, and Labrador Sea Water was considered. The results were used in combination with mass fluxes in order to determine the transports taking place in the region and analyze the variability observed both in the direction and magnitude of the fluxes, as well as to determine the relative contribution of each water mass to the flows. The high variability of the area was evident in the changes in flux direction and magnitude; the total input into the POMME region varied from POMME 1 (3.8 Sv southward) to POMME 3 (8.8 Sv northward). Our findings, depending on the cruise considered, corroborate most of the previous and often conflicting studies in the area, both in the flow direction and magnitude, suggesting that in highly dynamic areas such as this one, estimating annual trends from individual cruises might not provide accurate descriptions of the overall transports.