The turbulent dynamics of shoaling internal waves

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Despite their abundance, Canada's fresh water resources, a key element for economic and recreational activities, are being threatened.  One must only ponder the contaminated water in Walkerton, the immense flooding in Manitoba and Québec, the collapse of fisheries, the colonization by the zebra mussel and the leaching toxins from industrial sites such as the Love Canal, to realize how our economic activities and demand for water are adversely impacting the sustainability of Canada's natural aquatic systems.  A vital tool in the management of these resources is the combined hydrodynamic and water-quality computer model, which is uniquely capable of running both diagnostic and predictive simulations.  The accuracy of these models is limited by the necessity to reproduce a range of interconnected complex environmental flows, e.g. the Gulf Stream occurring over 1000s of kilometres, breaking waves occurring over meters and turbulent mixing occurring over millimetres.  Consequently, it is necessary to understand the basic processes occurring at each of these scales.  The objective of this study is to investigate one of these processes - the shoaling and breaking of internal waves - using controlled laboratory experiments and idealized computer simulations.  Internal waves form below the surface of stratified waterbodies (e.g. lakes, atmospheres and oceans), and like their surface counterparts, they break upon sloping topography.  Breaking internal waves locally mix the stratifying layers, which normally inhibit vertical transport of fluid.  This process has significant implications ranging from regulating the aquatic bio-chemistry to controlling large-scale circulation patterns that influence the global-ocean climate.  Specialized training will be provided for one Doctoral and four Master's students in the application of physical modelling, image analysis and computer simulations to perform the first ever detailed study of the three-dimensional dynamics and mixing processes associated with internal wave breaking on sloping topography.  The ultimate objective being to better represent these processes in the computer models used to manage Canada's inland and coastal water resources.