Water Quality in Coastal Zones under Variable Climatic Conditions

Abstract

A methodology to investigate the influence of local hydrometeorological conditions on water quality in the coastal zone is developed, first under existing and then under changing climatic conditions. The methodological approach consists of two steps: (1) the local climatic characteristics, such as winds and temperature, are linked by a stochastic model to the global atmospheric circulation patterns (CP). By use of available data of daily CP in the Mediterranean, local meteorological conditions can be simulated. A conditional stochastic model is used for this linkage. The results of simulation of global circulation models may then be taken into consideration to obtain different local climatic conditions. (2) Meteorological parameters, such as wind and temperature obtained in the first step are used as controlling factors in a hydrodynamic model of coastal circulation coupled with an ecological model. As an example of application of this second step, the models have been used in the case of Thermaikos bay (N. Greece), where data are available. One of the main sources of pollution in the bay is sewerage from the city of Thessaloniki, which is to be treated to different degrees in the years to come. Results of the simulation can be used to recommend optimum sewerage treatment so as to minimize the risk of water pollution in the coastal zone under variable climatic conditions.