Atlantic Water Inflow Through the Yermak Pass Branch: Evolution Since 2007

• Published in: Journal of Geophysical Research: Oceans
• Main Authors: Artana, Camila, Provost, Christine, Koenig, Zoé, Athanase, Marylou, Asgari, Ava
• Other Authors: Mercator Océan, Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Service hydrographique et océanographique de la Marine-Centre National de la Recherche Scientifique (CNRS)-Météo-France, Austral, Boréal et Carbone (ABC), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Norwegian Polar Institute, Alfred Wegener Institute for Polar and Marine Research (AWI), H2020 Arctic Passion project, grant number 101003472, ANR-10-EQPX-0032,IAOOS,Système d'observation de la glace, de l'atmopshère et de l'océan en Arctique(2010), ANR-14-AORS-0003,PAN-ARCTIC OPTIONS,PAN-ARTIC OPTIONS: HOLISTIC INTEGRATION FOR ARCTIC COASTAL-MARINE SUSTAINABILITY(2014), European Project: 603887,EC:FP7:ENV,FP7-ENV-2013-two-stage,ICE-ARC(2014)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2022
• Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; Arctic; Sea ice; Yermak plateau
• Online Access: https://hal.science/hal-03562925; https://hal.science/hal-03562925/document; https://hal.science/hal-03562925/file/manuscript-69.pdf; https://doi.org/10.1029/2021jc018006

International audience Thirty-four months (2017–2020) of mooring data were recently obtained at 80.6°N, 7.26°E in the main branch of Atlantic Water inflow to the Arctic, the Yermak Pass Branch. The Yermak Pass Branch was sampled at that same location during 14 months a decade ago (2007–2008) when sea ice was abundant (mean sea-ice concentration of 74% vs. 39% during the recent deployment). We focus on time scales larger than 50 hr. The new mooring data set shows an increase in the velocity variations of 40% compared to the 2007–2008 period. Year 2018 was exceptional with ice-free conditions over the entire year and an intensified mesoscale activity compared to other years. Temperature and salinity time series at 340 m showed significant trends over 3 years (freshening of −0.07 g/kg and cooling of about −0.9°C in 3 years). The performance of 1/12° Mercator-Ocean operational model at the mooring location was precisely assessed. The modeled Atlantic Water transport was on average larger during 2017–2020 (40% larger) than during 2007–2008. The synoptic transport time series ranged between −1 and 5 Sv over 2007–2020 and showed large seasonal and interannual variations. The transport was larger in winter than summer. However, occasionally negative transport (<−0.7 Sv) through the Yermak Pass Branch occurred during winters (“Blocking events”). These blocking events are associated with recirculations and eddy activity and were more common over the last years from 2016 onward. The model suggested that a Northern Branch crossing the Yermak Plateau further north (81.6°N) intermittently developed.