Extensive slope currents and the ocean-shelf boundary

Slope currents are one manifestation of ocean-shelf interaction, which is reviewed for length scales comparable with or greater than the shelf or slope width. Coastal trapped wave forms provide a basis for describing sub-inertial-frequency flow in the shelf-slope context. Such waves propagate cyclonically around ocean basins (a bias extending to energy propagation) and eventually decay through energy loss by friction, scattering or radiation. I discuss implications for remote forcing, for the along-shelf development of forced flows of all kinds, for the on-shelf penetration of oceanic flow structures (according to length and frequency scales and the degree of dissipation) and hence for coastal monitoring of oceanic circulation.