Transport of newly ventilated deep water from the Iceland Basin to the Westeuropean Basin

Increased values of trichlorofluoromethane (CFC-11), tritium and stable tri tium in the depth range from 2500 to 3500 m at the eastern flank of the Mid -Atlantic Ridge at 48 degreesN (WHP section A2) indicate an influence of ne wly ventilated water. Water with similar Theta, S and tracer properties is found on the WHP section Al (55 degreesN) situated north of the Gibbs Fract ure Zone in the Iceland Basin. The high tracer concentrations are due to th e influence of Iceland Scotland Overflow Water (ISOW). The ISOW-influenced water found in the Iceland Basin partially passes by the Gibbs Fracture Zon e (52 degreesN) and flows southward along the topography of the Mid-Atlanti c Ridge. A quantitative analysis of the transport from the Iceland Basin to the Westeuropean Basin is carried out based on the assumption that the wat er with enhanced tracer values is a two-component mixture of recirculating North East Atlantic Deep Water from the eastern part of the Westeuropean Ba sin and ISOW-influenced water as found on Al in the Iceland Basin (NEADW(IB )). The composition of the mixture and the transport time for the NEADW(IB) are deduced from the temporal evolution of the tracer values. From the dis tance between the two sections and the area with enhanced tracer values, a transport of NEADW(IB) from the Iceland Basin to the Westeuropean Basin of 1.63 +/- 0.32 Sv(1) is calculated for the density range 41.37 <<sigma>(3) < 41.475. Transports between 2.4 and 3.5 Sv result if the transport in the f ormer density range is extrapolated to 41.35 <sigma (3) <41.52 (correspondi ng to <sigma>(..) 27.8) in different ways. (C) 2001 Elsevier Science Ltd. A ll rights reserved.