The shelf break is a region of steep slopes, strong narrow currents, internal tides, shelf waves and significant vertical motion. Modellers have often regarded the shelf break as the nominal seaward boundary of shelf models or the coastal boundary of deep sea models. Even with the finest resolutions in ocean general circulation models, the shelf region is poorly resolved with only a few grid points. Ocean observers have difficulty in securing measurements at the edge of the shelf due to the narrowness of the currents and the steep slopes.
IAPSO has proposed the setting up of a new international programme to look at Deep Ocean Exchanges with the Shelf (DOES). The primary goal of DOES will be to understand the physical and chemical interactions that take place at the shelf break between the deep ocean currents and the shelf circulation. The IAPSO proposal will be described in this talk.
DOES will include:
* physical processes due to shelf waves, internal tides, shelf break upwelling,
* chemical and biological flux exchanges between the deep ocean and coastal ecosystems,
* river and estuary inputs of sediment and fresh water,
* coupled physical-chemical-biological numerical models that have a better description of the exchanges at the shelf edge,
* the influence of ocean physics around the shelf break on fisheries and climate,
* dissipation of tidal motion along the continental margins,
* flows over sills. |
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