Downward flow of dense water leaning on a submarine ridge
2007 (English)In: Deep Sea Research Part I: Oceanographic Research Papers, ISSN 0967-0637, Vol. 54, no 7, 1173-1188 p.Article in journal (Refereed) Published
Large-scale dense bottom currents are geostrophic to leading order, with the main flow direction along the continental slope. Bottom friction makes the water descend to greater depths, but only at a small angle to the horizontal. Here the effect of a submarine ridge that intersects the slope is considered. It is shown that the presence of a submarine ridge greatly enhances the downward transport. By leaning against the ridge it is possible for the dense water to flow downhill, perpendicular to the depth contours, even though the first-order dynamics are geostrophic. The requirement for downward flow next to the ridge is that the frictional transport that it induces is sufficiently large to counteract geostrophic advection along the isobaths and out of the ridge region. The dynamics are similar to those of downward flow in submarine canyons, but ridges appear to be more effective in channeling the dense water downhill, in particular for narrow ridges/canyons with small seaward slope of the ridge/canyon axis. The downward flow is analyzed using a simplified analytical model and the results are compared to data from the Filchner Overflow, which agree qualitatively with the model.
Place, publisher, year, edition, pages
2007. Vol. 54, no 7, 1173-1188 p.
topographic steering, dense plume, density current, ekman transport, secondary circulation, filchner overflow, Antarctica, Weddell sea
Oceanography, Hydrology, Water Resources
IdentifiersURN: urn:nbn:se:su:diva-55878DOI: 10.1016/j.dsr.2007.04.007ISI: 000248249400008OAI: oai:DiVA.org:su-55878DiVA: diva2:407573
authorCount :22011-03-312011-03-302011-03-31Bibliographically approved