Wind-induced barotropic oscillations around the Saint Pierre and Miquelon archipelago (North-west Atlantic)

Type Article
Date 2020-04
Language English
Author(s) Bezaud Marion1, Lazure PascalORCID1, Le Cann Bernard2
Affiliation(s) 1 : Ifremer, Laboratoire D'Océanographie Physique et Spatiale (LOPS), IUEM, Brest
2 : CNRS, Laboratoire D'Océanographie Physique et Spatiale (LOPS), IUEM, Brest
Source Continental Shelf Research (0278-4343) (Elsevier BV), 2020-04 , Vol. 195 , P. 104062 (19p.)
DOI 10.1016/j.csr.2020.104062
Keyword(s) Barotropic modelling, Wind induced oscillations, Continental shelf wave, Saint Pierre and Miquelon archipelago, Newfoundland
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 to 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.

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