Heat contents, thermal stabilities and Birgean wind work in Dystrophic Tasmanian Lakes and Reservoirs

Abstract

Values of whole-lake standard energy parameters (heat content, thermal stability and Birge's work of the wind) for ten dystrophic standing waters from western Tasmania were lower than expected for lakes of their depth and area. Although controlled principally by morphometric factors, the degree of shelter from wind and the extent of each lake's dystrophy also had considerable effects. These factors allowed only surface waters to contribute to the annual heat exchange cycle, thereby reducing the magnitude of each lake's heat budgets and influencing stability and wind work values. The lakes show considerable short- and long-term fluctuations in heat content, stability and wind work values in response to the capricious maritime meteorological conditions of the area. However, long periods between successive samplings may have caused some underestimation of the ranges of these three parameters. Despite this, the study reveals that these standard energy parameters are effective in describing the annual energy input and resistance to wind-induced mixing of these dystrophic Tasmanian lakes.