Empirical Predictors of Annual Surface Water Temperature Cycles in North American Lakes
Annual surface water temperature cycles of temperate zone lakes can be adequately described by a symmetrical sine wave of distinct amplitude and duration. The relationships between these sine wave components and climatic and morphometric variables were analyzed for 87 lakes spread over most of North America, and for 25 lakes located in south-central Ontario, Canada. Multiple regression equations are reported which permit estimation of the maximum annual surface water temperature (amplitude: AP) and the number of ice-free days (duration: DR) for a specific lake from data on long-term mean annual air temperature (TEMP), mean depth [Formula: see text], and fetch (FT). These estimates can be used to calculate mean surface water temperature for just the ice-free period or for an entire year.