A poleward flow along the Atlantic coast of the Iberian peninsula

Satellite Advanced Very High the continental slope of the Atlantic coast of Resolution Radiometer (AVHRR) imagery and Argos the Iberian Peninsula in a narrow (approximately tracked drifters have revealed the existence of a 100 km) vein, centered at a depth around 1000 m narrow, warm surface poleward current along the (Lacombe, 1971; Reid, 1979). Some recent Iberian coast during autumn and winter. Six observations (Ambar, 1984; 1985) indicate that near-surface drifter tracks indicated a net this poleward flow may extend from the bottom of northward flow between September 1986 and March the MIW (1600 m) to the top of the North Atlantic 1987, although individual drifter trajectories Central Water (NACW), i.e., the bottom of the also provided evidence of eddy activity and surface mixed layer at 100-200 m depth. Such episodes of equatorward flow. A SeaSoar survey poleward flows bound to the continental slope are during September 1986 in the region 37o-43oN, thought to be a common feature of sub-tropical 9o-11oW showed that poleward flow at that time eastern boundary regions (Wooster and Reid, was associated with the northward advance of a 1963). While there are numerous short term warm, salty tongue of water throughout the upper observations to show that similar flow can occur 400 m layer. Infra-red imagery confirmed the all along the eastern boundary of the northward penetration of the warm current and its sub-tropical gyre (Barton, 1989), few systematic progression around Cape Finisterre along the or long term observations are available to define north coast of Spain during the course of the the meridional extent and continuity of the winter. A similar situation is indicated by undercurrent. In other, similar areas, e.g., satellite imagery during other years. Current California (Huyer, 1983), it is found that during meter data show that poleward flow occurred along the upwelling season, when the trade winds the continental slope down to depths greater than dominate, the surface flow is equatorward over 600 m. Conductivity, temperature, and depth (CTD) the shelf, but may become poleward at times of casts show the presence of Mediterranean weak or northward wind. The seasonal variation Intermediate Water (MIW) at depths greater than of the surface flow off the Iberian coast is not 600 m. The MIW does not flow as a simple well established. northward flowing jet along the continental slope In September to October 1986, a cruise was off Iberia, but instead shows evidence of eddies undertaken off the Iberian coast to investigate within the flow. The poleward surface current is conditions over the continental margin. The in the opposite sense to the general summer resultant data set indicates that the season of circulation of the region, when cool upwelled upwelling had finished and that a regime of water is advected equatorward. It is postulated northward flow over the continental shelf and that the poleward flow is generated by slope was being established. In this paper, we thermohaline forcing when the southward trade describe characteristics of the circulation based winds, characteristic of the summer months, on shipboard, drifting buoy, and moored current weaken or reverse. Intermittent poleward flow meter observations. Satellite sea surface appears to be a common characteristic of the temperature imagery from a number of years Eastern Boundary throughout the North Atlantic (1982-1989) is used to show that the presence of from west Africa to the Norwegian Sea. a warm water mass extending along the Atlantic