Physical processes in Toronto Harbour depend in a large degree on the physical processes in Lake Ontario. In all of the the Great Lakes the physical processes are driven primarily by atmospheric forcing (wind stress, air pressure and temperature) and surface heat fluxes. In addition to the combination of these factors, the lake’s bathymetry makes circulation patterns unique and complex [8, 9].
The physical processes in the lake are either initiated by or associated with the factors described above. For example, wind stress induces seiches and different types of internal waves such as Poincaré waves, Kelvin waves, and coastal jets. Temperature is the other main forcing factor that determines the circulation in lakes. The Great Lakes are considered dimictic lakes, and therefore, have a period when the water column experiences thermal stratification and a period of almost uniform water temperature. Temperature stratification creates a density interface (Fig.1) that together with the effect of the rotation of the Earth plays an important role in the development of circulation in large lakes at mid latitudes like the Great Lakes.
Fig. 1. Water column temperature in Lake Ontario nearshore Toronto Harbour. Black line is the thermocline.
Bogdan Hlevca - University of Toronto Scarborough
bogdan (at) hlevca.com
1) The study is part of a large project spanning over several years done in collaboration with Carleton University, Toronto Regional Conservation Authority, Department of Fisheries and Oceans Canada and University of Toronto
2) The project aims to determine whether:
conditions in Toronto Harbour can sustain fish stocks, in particular warm water fish
to understand to what degree restoration work done at specific locations have affected the selection of habitat by various species of fish.
Provide a basis for future management of the area.
3) At U of T our aim was to characterize physical processes and understand the causes of temperature variability and currents, which are factors that can influence water quality and selection of habitat.
4) Toronto Harbour is located within the temperate climate zone, therefore experiences large variations of temperatures between the cold and warm season. (background picture)
5) However, our aim was determine the physical processes patterns at fine spatio-temporal scales especially during pre-, post- and stratified periods and its effect on fish movements.