The dynamics of Southern Ocean storm tracks

• Published in: Journal of Physical Oceanography
• Main Authors: Chapman, Christopher, Hogg, Andrew, Mcc, Kiss, Andrew, Rintoul, Stephen
• Other Authors: Research School of Earth Sciences ANU, Canberra (RSES), ANU College of Science Canberra, Australian National University (ANU)-Australian National University (ANU), Commonwealth Scientific and Industrial Research Organisation Canberra (CSIRO), 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), University of New South Wales Canberra Campus (UNSW), CSIRO Wealth from Oceans Flagship, Australian Commonwealth Government CSIRO Wealth from Oceans Flagship scholarship Australian Research Council Australian Governments Cooperative Research Centre's Program, through the Antarctic Climate and Ecosystems Cooperative Research Centre (ACE CRC) Department of Environment, Bureau of Meteorology CSIRO through the Australian Climate Change Science Program
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2015
• Subjects: Geographic location/entity; Southern Ocean; Circulation/ Dynamics; Eddies; Nonlinear dynamics; Ocean dynamics; Stationary waves; Waves; oceanic; [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph]
• Online Access: https://hal.sorbonne-universite.fr/hal-01837099; https://hal.sorbonne-universite.fr/hal-01837099/document; https://hal.sorbonne-universite.fr/hal-01837099/file/chap1.pdf; https://doi.org/10.1175/JPO-D-14-0075.1

International audience The mechanisms that initiate and maintain oceanic “storm tracks” (regions of anomalously high eddy kinetic energy) are studied in a wind-driven, isopycnal, primitive equation model with idealized bottom topography. Storm tracks are found downstream of the topography in regions strongly influenced by a large-scale stationary meander that is generated by the interaction between the background mean flow and the topography. In oceanic storm tracks the length scale of the stationary meander differs from that of the transient eddies, a point of distinction from the atmospheric storm tracks. When the zonal length and height of the topography are varied, the storm-track intensity is largely unchanged and the downstream storm-track length varies only weakly. The dynamics of the storm track in this idealized configuration are investigated using a wave activity flux (related to the Eliassen–Palm flux and eddy energy budgets). It is found that vertical fluxes of wave activity (which correspond to eddy growth by baroclinic conversion) are localized to the region influenced by the standing meander. Farther downstream, organized horizontal wave activity fluxes (which indicate eddy energy fluxes) are found. A mechanism for the development of oceanic storm tracks is proposed: the standing meander initiates localized conversion of energy from the mean field to the eddy field, while the storm track develops downstream of the initial baroclinic growth through the ageostrophic flux of Montgomery potential. Finally, the implications of this analysis for the parameterization and prediction of storm tracks in ocean models are discussed.