Northern Current variability and its impact on the Blanes Canyon circulation: A numerical study

Abstract

A high-resolution (∼1.2km) 3D numerical model was used to analyze the interaction of the Northern Current (a right-bounded flow) with the Blanes submarine canyon (BC, NW Mediterranean). Although it refers to a climatological simulation the model properly suites our purpose since it simulates the Northern Current (NC) mesoscale variability, as well as its seasonal variability. Model results were validated with satellite sea surface temperature and current-meter data. The simulated NC tends to be faster and deeper in winter, and slower and shallower in summer. According to our results, NC meanders and eddies are recurrent in the BC area and produce highly fluctuating three-dimensional circulation patterns within the canyon. We found that NC meanders and anticyclonic eddies propagating along the current pathway tend to be deep and, consequently, their effects extend down to the deeper part of the BC. We also found that the meandering of the NC plays a key role in enhancing vertical motions inside the BC. Upwelling and downwelling events occurring on timescales of 4–20days are associated with NC meanders crests and troughs passing over the BC. Net upwelling/downwelling events are accordingly influenced by the NC seasonality. They are more predominant in winter, while damped in summer. Our results show the importance of NC meanders in creating local net upwelling/downwelling and strengthen the evidence that continuous right-bounded (downwelling favorable) flows can also produce net upwelling inside submarine canyons.