Do Physical Oceanographers Care About Coastal Processes in Water Less Than 20-m Deep?

The resounding yes may surprise Arctic researchers and old-style oceanographers, but the physics of coastal waters less than 20-m deep has been the subject of intense experimental and theoretical study over the last decade by physical oceanographers. For example, discoveries on the dynamics of (often sediment ladden) freshwater discharges into the coastal ocean relate to many Arctic systems that receive freshwater from rivers and ice melt. Boundary layer processes due to bottom and surface friction, too, often dominate coastal dynamics. Material transport and fluxes both along and across the coastal zone are strongly affected by stress- and buoyancy induced physical processes that mid-latitude physical oceanographers have explored extensively. Much of this progress has yet to migrate into the Arctic research community where oceanographers appear to focus on steady-state and deep-basin problems with little interest to processes impacted by the presence of a coastline and/or flow phenomena at the internal Rossby radius of deformation. This situation has left geological and biological scientists working on pressing Arctic coastal zone problems isolated from new advances, understanding, and technologies of exchange processes at the land-ocean interface that generally is less than 20-m deep. More specifically, I discuss published and unpublished observational and theoretical model results from both Arctic and mid-latitude inner shelf systems. The inner shelf is here defined as the region where surface and bottom boundary layers overlap. I will contrast data from the Canadian Mackenzie and Russian East Siberian shelf seas with similar data (and models to explain them) from North- and South-American inner shelves. I will demonstrate conceptionally how frictional and buoyancy forces interact in waters less than 20-m deep to cause circulations, vertical stratification, and depth-dependent material transport that differs substantially from steady and linear perceptions of a bygone era. I will also demonstrate how observational techniques in physical oceanography have advanced far beyond the conventional water sampling and analyses to include direct velocity observations in space and time. The inner shelf of the coastal ocean emerges as a dynamically rich, complex, and unsteady environment that varies in space and time at predictable scales. Failure to properly resolve these scales in experimental design cause unanticipated aliasing and mis-interpretation of environmentally sensitive biogeochemical fields and underlying processes.