1.3
DIURNAL TEMPERATURE VARIATION IN A SHALLOW WATER POOL

Adrie F G. Jacobs, Wageningen Agricultural Univ, Wageningen, The Netherlands; and B. G. Heusinkveld and J. P. Nieveen

The growth and development of cold blooded water organisms is strongly influenced by temperature. In many ecological models, air temperature or "bulk water" temperature is used as an input parameter. However, organisms that live close to the water surface in shallow waters, such as larvas of mosquito species, are exposed to temperatures which differ considerably from the air or bulk water temperature. The goal of the present research is, first, to develop a simple one-dimensional model to simulate the temperature profile within small water bodies. The second goal is conduct an outdoor experiment to estimate the model input parameters and to verify the model for a shallow water pool.
The model simulations as well as the measurements show that during daytime a strong temperature stratification occurs in the water. This stratification is strongly dependent on wind speed and is dependent on the vegetation of the surrounding environment of the water body. Throughout the night, however, a well mixed layer develops growing from the water surface.
Qualitatively, the model simulations agree with the measurement results. Quantitatively, however, it appears that for a small water body the one-dimensional model is too simple to simulate the temperature behavior of small water bodies accurately due to the spatial variability of the water body. Also it appears that the temperature behavior is very sensitive to the extinction coefficient for short wave radiation which is closely related to the suspension of fine particles in the water.

The 13th Conference on Biometeorology and Aerobiology