Comparison of the performance of five different water quality models of the North Sea

During an international workshop, held within the auspices of the ASMO (Assessment and Monitoring) group of OSPARCOM (Oslo and Paris Commissions), the performance of five different water quality models of the North Sea was compared. Selected substances were cadmium, PCB-153, two PAHs (fluoranthene and benzo[a]pyrene) and atrazine. However during the workshop it appeared that it was only possible to compare the cadmium results of five models. The modelled concentrations were validated with a common field data set in different areas of the North Sea. Also the results of the responsiveness to a 50% reduction in the input were compared. In general it appeared that there is a lack of quality controlled field data to calibrate and validate the models. It was remarkable that the calculated concentrations of cadmium were low compared to the measured data. The performance of the models in the 50% reduction scenario appeared to be sensitive for the boundary conditions.