• Login
    About WHOAS
    View Item 
    •   WHOAS Home
    • Woods Hole Oceanographic Institution
    • Academic Programs
    • WHOI Theses
    • View Item
    •   WHOAS Home
    • Woods Hole Oceanographic Institution
    • Academic Programs
    • WHOI Theses
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Browse

    All of WHOASCommunities & CollectionsBy Issue DateAuthorsTitlesKeywordsThis CollectionBy Issue DateAuthorsTitlesKeywords

    My Account

    LoginRegister

    Statistics

    View Usage Statistics

    Overflows and upper ocean interaction : a mechanism for the Azores Current

    Thumbnail
    View/Open
    Kida phd thesis.pdf (22.06Mb)
    Date
    2006-09
    Author
    Kida, Shinichiro  Concept link
    Metadata
    Show full item record
    Citable URI
    https://hdl.handle.net/1912/1762
    Location
    Cape St. Vincent
    DOI
    10.1575/1912/1762
    Keyword
     Ocean circulation; Computer simulation 
    Abstract
    The oceanic response to overflows is explored using a two-layer isopycnal model. Overflows are a major source of the dense water of the global deep ocean, originating from only a few marginal seas. They enter the open ocean as dense gravity currents down a continental slope and play a crucial role in the deep ocean circulation. To understand the dynamics of these overflows, previous studies simplified their dynamics by treating the overlying ocean as inactive. This simplification may be a first approximation for the overflow but not for the overlying ocean. The Mediterranean overflow, for example, entrains about 2 Sv of overlying Atlantic water when it enters the Atlantic through Gibraltar Strait. The upper ocean must balance the mass loss and vortex stretching associated with entrainment. Thus for the upper ocean, overflows represent a localized region of intense mass and PV forcing. The simulations in this study show that in the upper layer, entrainment forces a cyclonic circulation along bathymetric contours. This is a topographic β-plume and its transport depends on the entrainment region size and the topographic slope. Baroclinic instability also develops and creates eddy thickness flux to the in-shore direction, forcing a double gyre topographic β-plume near the strait due to eddy PV flux convergence on the in-shore side of the continental slope and divergence on the offshore side. When the upper oceanic response to overflows is examined specifically for the Mediterranean overflow, the upper ocean is found to establish two trans-Atlantic zonal jets, analogous to the Azores current and the Azores Counter current. These two zonal jets are an extension of the topographic β-plume driven by the overflow. Because the eddies in the steep slope region near Cape St. Vincent drive a mean flow across the slope, the topographic β-plume connects to the Atlantic Ocean to become a basin scale flow. This thesis shows that overflows can induce a significant circulation in the upper ocean, and for the Mediterranean overflow, this circulation is a basin scale flow.
    Description
    Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 2006
    Collections
    • WHOI Theses
    • Physical Oceanography (PO)
    Suggested Citation
    Thesis: Kida, Shinichiro, "Overflows and upper ocean interaction : a mechanism for the Azores Current", 2006-09, DOI:10.1575/1912/1762, https://hdl.handle.net/1912/1762
     

    Related items

    Showing items related by title, author, creator and subject.

    • Thumbnail

      Understanding the ocean carbon and sulfur cycles in the context of a variable ocean : a study of anthropogenic carbon storage and dimethylsulfide production in the Atlantic Ocean 

      Levine, Naomi M. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2010-02)
      Anthropogenic activity is rapidly changing the global climate through the emission of carbon dioxide. Ocean carbon and sulfur cycles have the potential to impact global climate directly and through feedback loops. Numerical ...
    • Thumbnail

      A modal/WKB inversion method for determining sound speed profiles in the ocean and ocean bottom 

      Casey, Kevin D. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1988-06)
      Two approaches to determining the ocean sound speed profile using measured acoustic modal eigenvalues are examined. Both methods use measured eigenvalues and mode dependent assumed values of the WKB phase integral as ...
    • Thumbnail

      Scale closure in upper ocean optical properties : from single particles to ocean color 

      Green, Rebecca E. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2002-06)
      Predictions of chlorophyll concentration from satellite ocean color are an indicator of phytoplankton primary productivity, with implications for foodweb structure, fisheries, and the global carbon cycle. Current models ...
    All Items in WHOAS are protected by original copyright, with all rights reserved, unless otherwise indicated. WHOAS also supports the use of the Creative Commons licenses for original content.
    A service of the MBLWHOI Library | About WHOAS
    Contact Us | Send Feedback | Privacy Policy
    Core Trust Logo