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

• Published in: Continental Shelf Research
• Main Authors: Bezaud, M, Lazure, P., Le Cann, Bernard
• Other Authors: Laboratoire d'Océanographie Physique et Spatiale (LOPS), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2020
• Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces; environment; North West Atlantic
• Online Access: https://hal.science/hal-02890244; https://hal.science/hal-02890244/document; https://hal.science/hal-02890244/file/Bezaud_et_al_accepted.CSR2020.pdf; https://doi.org/10.1016/j.csr.2020.104062

International audience 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 northwest 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.