Transports and variability-driving mechanisms in Flemish Pass at the western boundary of the subpolar North Atlantic (FLEPVAR)

• Applicants: Dr. Kerstin Jochumsen; Dr. Dagmar Kieke
• Subject Area: Oceanography
• Term: from 2011 to 2015
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 206548004

Labrador Sea Water (LSW) formed in the Labrador Sea constitutes the lightest contribution to North Atlantic Deep Water (NADW), a conglomerate of water masses that form the cold return flow of the Atlantic meridional overturning circulation (MOC). Climate variability can be modulated by changes in the MOC strength; such changes are thought to be linked to variations in LSW formation. The Deep Western Boundary Current (DWBC) is the main southward pathway for newly formed LSW. Topographic obstacles at the southern exit of the Labrador Sea split the DWBC into an upper branch carrying LSW through Flemish Pass (~1200m sill depth) and a branch carrying all NADW components along the continental slope around Flemish Cap. Up to now, transports through Flemish Pass and their contribution to the MOC are still uncertain, the importance of the pass for the export of LSW and its associated variability are yet unknown. In this project the transports through Flemish Pass will be quantified, and mechanisms driving and governing the variability of the flow will be investigated.The project focuses on the following questions: What is the magnitude of transports for waters passingthrough Flemish Pass and their associated variability? Which processes drive the variability? What is the relevance of the deep water export through Flemish Pass for the MOC, especially when compared to the DWBC export? Are both deep water export pathways (through Flemish Pass or around Flemish Cap) coupled? What processes govern the inflow of deep water into Flemish Pass? To answers these questions, ship-based measurements and time series from moored instruments in the Flemish Pass will be analyzed in conjunction with output from two state-of-the-art ocean models run at high-resolution.

• DFG Programme: Research Grants
• Major Instrumentation: 2 ADCP-Strömungsmesser + 2 Auftriebsbojen
• Instrumentation Group: 8860 Geschwindigkeitsmeßgeräte (außer 047, 053, 192 und 244)