The source of the Canary current in fall 2009

Abstract

The source of the Canary Current has been inferred from an inverse box model appliedto the hydrographic data of a survey carried out in 2009 in the northeast subtropical gyre(29–37N, 9–24W). The Portugal Current is observed between 13.5 and 14.8W at 37N carrying 1:8+-0:4 Sv southward. This current presumably merges with the eastwardtransport of the Azores Current System and partly contributes to the Mediterranean inflowand partly to the northward recirculation of the Azores Current through the Gulf of Cadiz.The Azores Current System is located in the meridional range 33.50–36.25N at 24.50W.This System transports eastward 7:260:5 Sv in the thermocline layers and 1:160:8Svatintermediate layers. The Azores Current intermediate water mass has the highest portion ofSub-Arctic intermediate water (SAIW) in the region, while the Azores Countercurrentintermediate waters mass is mainly Mediterranean water. The Canary Current extends from 22.25 to 18.50Wat29N, the westernmost position ever observed. This current transports southward -6:2+-0:6 Sv in the thermocline layers and-2:0+-0:8 Sv in the intermediatelayers. This intermediate flow shows a relative maximum of oxygen and a relativeminimum in nutrient concentration, indicating the presence of SAIW. The study concludesthat, at least in fall 2009, the Canary Current extends to the intermediate waters(n<-27:9220 approximately 1600 dbar) and that Azores Current feeds the Canary Currentat surface and intermediate layers.