Some effects of water bodies on the n environment – numerical experiments

A three-dimensional micro-scale model was used to study some aspects of water bodies on the urban environment. This is of special importance in the field of urban climate, where ways and means to reduce the heat load produced by city residents need to be found. In a systematic study, the ranges and impacts for different sizes of water bodies were estimated and a fitted relation was given. Water temperature, and the resulting temperature contrast with the surrounding area, seems to be more important during nighttime than during the day. The relevance of meteorological and morphological parameters on water surface temperature was studied by adding a water model to an existing numerical framework. The coupled model system was tested against field observations. Beside external radiation forcing, wind speed and depth of the water body were identified as the most relevant parameters. In a numerical study for a realistic urban environment the different impacts of water bodies during day and night were demonstrated, and the range of the penetration of the water effect into the built-up area was estimated.