Subpolar Southern Ocean Seasonal Variability of the Geostrophic Circulation From Multi-Mission Satellite Altimetry

• Published in: Journal of Geophysical Research: Oceans
• Main Authors: Auger, Matthis, Sallée, Jean-Baptiste, Prandi, Pierre, Naveira Garabato, Alberto C.
• Other Authors: Processus et interactions de fine échelle océanique (PROTEO), 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), Collecte Localisation Satellites (CLS), Ocean and Earth Science Southampton, University of Southampton-National Oceanography Centre (NOC)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2022
• Subjects: Southern Ocean; seasonal cycle; ocean circulation; satellite altimetry; [SDU]Sciences of the Universe [physics]; [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography; Antarctic; Curl; The Antarctic; Antarc*; Sea ice
• Online Access: https://insu.hal.science/insu-03746446; https://insu.hal.science/insu-03746446/document; https://insu.hal.science/insu-03746446/file/JGR%20Oceans%20-%202022%20-%20Auger%20-%20Subpolar%20Southern%20Ocean%20Seasonal%20Variability%20of%20the%20Geostrophic%20Circulation%20From%20Multi%25u2010Mission.pdf; https://doi.org/10.1029/2021JC018096

International audience A novel multi-satellite product is used to shed light on the sea surface height seasonal cycle and associated geostrophic circulation in the subpolar Southern Ocean. We find three main modes of variability governing the Sea Level Anomaly seasonal cycle, all of them primarily governed by wind forcing. The main mode of seasonal variability is associated with the seasonality of the main subpolar gyres governed by large-scale wind stress curl, qualitatively consistent with Sverdrup dynamics. The second seasonal mode is related to the Antarctic Slope Current (ASC), governed by the coastal easterlies, with a rapid circumpolar propagation of anomalous sea-level along the continental slope that is dynamically consistent with the so-called Southern Mode. The first two modes induce an acceleration of the gyres and the ASC in winter. The third seasonal mode appears to be driven by sea ice-modulated surface stress and induces an offshore extension of the ASC from autumn to winter.