DIURNAL TEMPERATURE-FLUCTUATIONS IN A NATURAL SHALLOW-WATER BODY

For many biological processes, the diurnal and annual behavior of the temperature of the water layer close to the water surface is very impo rtant. A simple one-dimensional model has been developed to simulate t he temperature profile within small water bodies. An outdoor experimen t has been conducted to estimate the model input parameters and to ver ify the model. The model simulations as well as the measurements show that during daytime a strong temperature stratification occurs in the water. Throughout the night, however, a well mixed layer develops grow ing from the water surface. Qualitatively, the model simulations agree with the measurement results. Quantitatively, however, it appears tha t for a small water body the one-dimensional model is too simple to si mulate the temperature behavior of small water bodies accurately due t o the spatial variability of the water body. It also appears that the temperature behavior is very sensitive to the extinction coefficient f or short wave radiation which is closely related to the suspension of fine particles in the water. (C) 1997 Elsevier Science B.V.