New Hydrographic Measurements of the Upper Arctic Western Eurasian Basin in 2017 Reveal Fresher Mixed Layer and Shallower Warm Layer Than 2005–2012 Climatology

• Published in: Journal of Geophysical Research: Oceans
• Main Authors: Athanase, Marylou, Sennéchael, Nathalie, Garric, Gilles, Koenig, Zoé, Boles, Elisabeth, Provost, Christine
• Other Authors: 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), 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, 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 2019
• Subjects: Arctic ocean; hydrography; halocline eddies; Atlantic Water mesoscale structures; Mercator Ocean operational model; IAOOS (Ice Atmosphere Ocean Observing System); [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology; [SDU.STU.GL]Sciences of the Universe [physics]/Earth Sciences/Glaciology; amundsen basin; Arctic; Arctic Ocean; Fram Strait; Nansen Basin; Yermak plateau
• Online Access: https://hal.science/hal-03015373; https://hal.science/hal-03015373/document; https://hal.science/hal-03015373/file/Athanase_et_al-2019-Journal_of_Geophysical_Research__Oceans.pdf; https://doi.org/10.1029/2018JC014701

International audience In 2017, Ice Atmosphere Ocean Observing System autonomous drifting platforms provided extensive physical and biogeochemical data in the upper 350 m of the western Eurasian Basin through their 8‐month drift across the Amundsen Basin, the Gakkel Ridge, the Nansen Basin and western Fram Strait. Comparison with WOA13 climatology indicates a fresher surface layer and shallower warm layer in 2017 than in 2005–2012. The Ice Atmosphere Ocean Observing System 2017 data feature two halocline eddies in the Amundsen Basin and two Atlantic Water (AW) mesoscale structures in the Nansen Basin. Analysis of the global (1/12)° Mercator Ocean operational system suggests that the halocline eddies resulted from instabilities in the frontal zone between fresher Makarov waters and saltier Eurasian waters. This frontal region appears to have shifted further southeast in 2017 (near 88°N, 10°E) compared to 2005–2012. The operational system depicts the large AW structure in the Nansen Basin (140 km crossed as far as 83.7°N, 34.5°E) as an AW meander from the Arctic Circumpolar Boundary Current, which turned into an anticyclonic eddy about a month after the platforms drifted away. The AW structure at 82.8°N, 3°W, northwest of the Yermak Plateau, corresponds to an AW recirculating branch detaching from the Yermak Plateau slope back toward Fram Strait.