Wind Mixing and Restratification in a Lake near the Temperature of Maximum Density

Open Access
Publisher Website
Google Scholar
Abstract
The cooling of a freshwater take provides an opportunity for studying wind mixing and restratification under the peculiar conditions associated with a density maximum. The concepts are explored using a mixing-layer model that incorporates both nonlinearity and pressure dependence in the equation of state; the results provide a basis for interpreting temperature structure in Babine Lake and for making some more general observations on mixing and restratification. Following destruction of summer stratification by wind mixing and convection in autumn, the lake is essentially isothermal as it cools through 4°C. Near this temperature, the coefficient of expansion becomes so small that pressure effects, which play little part in the dynamics at higher temperatures, can dominate the stability. In effect, the depth at which the local temperature equals the temperature of maximum density at constant pressure marks the transition between forced and free convection. Above this transition depth, the wind mus... Abstract The cooling of a freshwater take provides an opportunity for studying wind mixing and restratification under the peculiar conditions associated with a density maximum. The concepts are explored using a mixing-layer model that incorporates both nonlinearity and pressure dependence in the equation of state; the results provide a basis for interpreting temperature structure in Babine Lake and for making some more general observations on mixing and restratification. Following destruction of summer stratification by wind mixing and convection in autumn, the lake is essentially isothermal as it cools through 4°C. Near this temperature, the coefficient of expansion becomes so small that pressure effects, which play little part in the dynamics at higher temperatures, can dominate the stability. In effect, the depth at which the local temperature equals the temperature of maximum density at constant pressure marks the transition between forced and free convection. Above this transition depth, the wind mus...

This publication has 0 references indexed in Scilit: