The AMOC and the seasonal cycle of the Canary Current

Abstract

Due to the important role of the eastern Atlantic in the Atlantic Meridional Overturning Circulation (AMOC), in this study we describe the seasonal cycle of the Canary Current system using hydrographic data from two cruises carried out in a box around the Canary Islands, the region where the eastern component of the RAPID array is placed. CTD, VMADCP and LADCP data were combined with inverse modelling in order to determine absolute geostrophic transports in the Canary Islands region in fall and spring. During spring, the overall transport of Canary Current (CC) and the transport in the Lanzarote Passage (LP) were southward. In the Lanzarote Passage (LP), between the Canary Islands and Africa, the transported was 0.6±0.20 Sv southward, while the Canary Current transported 1.0±0.40 Sv in the oceanic waters of the Canary Islands Archipelago. During fall, in the LP the transport was 2.8±0.4Sv northward, while the CC transported 2.9±0.60 Sv southward in the oceanic waters of the Canary Islands Archipelago. The amplitude of the seasonal cycle of the geostrophic transport obtained was quite similar to the seasonal cycle of the Eastern Atlantic contribution to the AMOC, as measured by the RAPID array. To understand the relationship between the seasonal cycle found in the CC and in the LP, and the amplitude of the seasonal cycle of the AMOC transport associated with Rossby waves, a sensitivity study of the Rossby wave model is included.