Upwelling velocity and ventilation in the Mauritanian upwelling system estimated by CFC-12 and SF6 observations

摘要: Transient tracer data (CFC-12 and SF6) from three oceanographic field campaigns to the Mauritanian Upwelling area conducted during winter, spring summer 2005 2007 is presented. The transient tracers are used constrain a possible solution time distribution (TTD) along 18°N quantify mean ages in vertical sections perpendicular coast. We found that an Inverse Gaussian where ratio of moments δ Γ equals 1.2 (δ/Γ=1.2) TTD. further show considerable under-saturation mixed layer winter cruises can only be maintained by mixing or upwelling tracer-poor water below layer. use dissipation microstructure measurements depth flux diffusivity wind ship air-sea flux. then magnitude estimate advective velocity which balance first two processes, steady state assumption. find velocities range less than 1 5.6×10-5ms-1 (<0.8-4.8md-1), with generally higher values close coast, but comparable winter. During cruise were equilibrium atmosphere, suggesting no upwelling. have shown CFC-12 SF6 for calculating velocity, overall uncertainty roughly ±50%.