Variability of the Antarctic intermediate waters in the Northern Canary Box

Several chemical parameters were measured during four seasonal cruises in 1997 and 1998 within the Canary Islands Açores Gibraltar Observations project, along the transects within the so-called Northern Canary Box (NCB). This area is enclosed between the African coast, latitudes 29°N and 32°N and longitude 18°W to the north of the Canary Islands (Spain). The nutrient and oxygen concentration data are used in order to establish the Atlantic Antarctic Intermediate Water (AAIW) distribution in the area. By means of an anomaly method, it is established that this water mass is widely found in this zone, particularly new to the African coast. A volumetric budget indicates that the AAIW volume flowing into the NCB is of the same order as the Mediterranean Water (MW) inflow. The results indicate that only 40% of the AAIW mass reaching the “Box” flows northwards through the 32°N section, whereas 20% returns southwards through the 29°N section.