Journal cover Journal topic
Ocean Science An interactive open-access journal of the European Geosciences Union
Journal topic

Journal metrics

IF value: 2.864
IF 5-year value: 3.337
IF 5-year
CiteScore value: 4.5
SNIP value: 1.259
IPP value: 3.07
SJR value: 1.326
Scimago H <br class='widget-line-break'>index value: 52
Scimago H
h5-index value: 30
Volume 5, issue 4
Ocean Sci., 5, 621–634, 2009
© Author(s) 2009. This work is distributed under
the Creative Commons Attribution 3.0 License.

Special issue: Deep ocean exchange with the shelf

Ocean Sci., 5, 621–634, 2009
© Author(s) 2009. This work is distributed under
the Creative Commons Attribution 3.0 License.

  07 Dec 2009

07 Dec 2009

Deep ocean exchange with west-European shelf seas

J. M. Huthnance, J. T. Holt, and S. L. Wakelin J. M. Huthnance et al.
  • Proudman Oceanographic Laboratory, 6 Brownlow Street, Liverpool L3 5DA, UK

Abstract. We review mechanisms and studies of exchange between the north-east Atlantic and the adjacent shelf seas. Well-developed summer upwelling and associated filaments off Portugal and north-west Spain give exchange O(3 m2/s per unit length of shelf). Prevailing westerly winds further north drive exchange O(1 m2/s). Poleward flow along most of the upper slope has associated secondary circulation O(1 m2/s), meanders and eddies. Eddies are shed from slope waters into the Bay of Biscay, and local exchanges occur at shelf spurs and depressions or canyons (e.g. dense-water cascading of order 1 m2/s). Tidal transports are larger, but their reversal every six hours makes exchange largely ineffective except where internal tides are large and non-linear, as in the Celtic Sea where solitons carry water with exchange O(1 m2/s). These various physical exchanges amount to an estimated 2–3 m2/s per unit length of shelf, between ocean and shelf. A numerical model estimate is comparable: 2.5×106 m3/s onto and off the shelf from Brittany to Norway. Mixing controls the seasonal thermocline, affecting primary production and hence fluxes and fate of organic matter. Specifically, CO2 take-up by primary production, settling below the thermocline before respiration, and then off-shelf transport, make an effective shelf-sea "pump" (for CO2 from the atmosphere to the deep ocean). However, knowledge of biogeochemical fluxes is generally sparse, giving scope for more measurements, model validation and estimates from models.

Publications Copernicus