Impact of partial steps and momentum advection schemes in a global ocean circulation model at eddy-permitting resolution

• Published in: Ocean Dynamics
• Main Authors: Barnier, Bernard, Madec, Gurvan, Penduff, Thierry, Molines, Jean-Marc, Tréguier, Anne-Marie, Le Sommer, Julien, Beckmann, Aike, Biastoch, Arne, Böning, Claus W., Dengg, Joachim, Derval, Corine, Durand, Edmée, Gulev, Sergei K., Rémy, Elisabeth, Talandier, Claude, Theetten, Sébastien, Maltrud, Mathew, Mcclean, Julie, de Cuevas, Beverly A.
• Other Authors: Laboratoire des Écoulements Géophysiques et Industriels Grenoble (LEGI), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'océanographie dynamique et de climatologie (LODYC), Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de physique des océans (LPO), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Division of Geophysics Helsinki, Department of Physical Sciences Helsinki, Helsingin yliopisto = Helsingfors universitet = University of Helsinki-Helsingin yliopisto = Helsingfors universitet = University of Helsinki, Leibniz-Institut für Meereswissenschaften (IFM-GEOMAR), Mercator Océan, Société Civile CNRS Ifremer IRD Météo-France SHOM, Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Shirshov Institut of Oceanography, Russian Academy of Sciences Moscow (RAS), Fluid Dynamics Group, Los Alamos National Laboratory (LANL), Scripps Institution of Oceanography (SIO - UC San Diego), University of California San Diego (UC San Diego), University of California (UC)-University of California (UC), National Oceanography Centre Southampton (NOC), University of Southampton
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2006
• Subjects: Global ocean; Eddy-permitting ocean model; Momentum advection scheme; Partial step topography; Eddy/topography interactions; [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph]; [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph]; [SDE.MCG]Environmental Sciences/Global Changes; Pacific; Indian; Zapiola; north atlantic current; North Atlantic; Orca; Sea ice
• Online Access: https://hal.science/hal-00138383; https://doi.org/10.1007/s10236-006-0082-1

http://www.springerlink.com/content/w8327463321564n3/fulltext.html Series of sensitivity tests were performed with a z-coordinate, global eddy-permitting (1/4°) ocean/sea-ice model (the ORCA-R025 model configuration developed for the DRAKKAR project) to carefully evaluate the impact of recent state-of-the-art numerical schemes on model solutions. The combination of an energy–enstrophy conserving (EEN) scheme for momentum advection with a partial step (PS) representation of the bottom topography yields significant improvements in the mean circulation. Well known biases in the representation of western boundary currents, such as in the Atlantic the detachment of the Gulf Stream, the path of the North Atlantic Current, the location of the Confluence, and the strength of the Zapiola Eddy in the south Atlantic, are partly corrected. Similar improvements are found in the Pacific, Indian, and Southern Oceans, and characteristics of the mean flow are generally much closer to observations. Comparisons with other state-of-the-art models show that the ORCA-R025 configuration generally performs better at similar resolution. In addition, the model solution is often comparable to solutions obtained at 1/6 or 1/10° resolution in some aspects concerning mean flow patterns and distribution of eddy kinetic energy. Although the reasons for these improvements are not analyzed in detail in this paper, evidence is shown that the combination of EEN with PS reduces numerical noise near the bottom, which is likely to affect current–topography interactions in a systematic way. We conclude that significant corrections of the mean biases presently seen in general circulation model solutions at eddy-permitting resolution can still be expected from the development of numerical methods, which represent an alternative to increasing resolution.