Wind-induced barotropic oscillations around the Saint Pierre and Miquelon archipelago (North-West Atlantic). (15th April 2020)

• Record Type: Journal Article
• Authors: Bezaud, M.; Lazure, P.; Le Cann, B.
• Is Part Of: Continental shelf research. Volume 195(2020)
• Publication Date: 2020-04-15
• Subjects: Barotropic modelling -- Wind induced oscillations -- Continental shelf wave -- Saint Pierre and Miquelon archipelago -- Newfoundland; Continental shelf -- Periodicals; Submarine geology -- Periodicals; 551.41
• DOI: 10.1016/j.csr.2020.104062
• Languages: English
• ISSNs: 0278-4343

Abstract

Abstract: We investigate the nearly barotropic oscillations recently observed around the Saint Pierre and Miquelon (SPM) archipelago. They were recorded by two ADCPs at about 30 m depth during winter and spring 2014. These oscillations were the dominant signal on the currents with a period of 2–4 days. Our analysis shows that these oscillations were triggered by the wind. To investigate these oscillations, a 2D numerical model was implemented at a regional scale. The results from a realistic simulation confirmed the impact of wind forcing on ocean dynamics in the region. They also showed amplification of these oscillations around SPM, particularly in the north-west of the archipelago and near Burin Peninsula. Analyses suggested the influence of continental shelf wave dynamics at a 'regional' scale. This regional wave then triggers a 'local' scale continental shelf wave propagating anticyclonically around SPM in ~2 days. Schematic modelling simulations with periodic wind stress forcing and relaxation after a gust of wind show a strong current response in this region with a wind stress periodicity centred around 2 days, which is attributed to resonance in the SPM area. Highlights: A new set of current measurements on the continental shelf of Saint-Pierre and Miquelon is presented. Current oscillations at periods of 2–4 days appear transiently and persist for several days. The atmospheric depressions that cross the region trigger these oscillations. These oscillations have characteristics of continental shelf waves. They rotate clockwise around Saint Pierre and Miquelon archipelago.