The Poseidon Operational Tool for the Prediction of Floating Pollutant Transport POLLANI ANNIKA *, TRIANTAFYLLOU GEORGE , PETIHAKIS GEORGE , NITTIS KONSTANTINOSà ,1 , DOUNAS COSTAS and CHRISTOFOROS KOUTITAS§ ,2  DepartmentofMarineTechnologyandManagementofNaturalResources,DivisionofMarineDynamicsandNumerical Simulations, Institute of Marine Biology of Crete, P.O. Box 2214, Iraklio, 71003 Crete, Greece àNational Center of Marine Research, Agios Kosmas, Helliniko, GR 16604, Greece §Department of Civil Engineering, Aristotle University of Thessaloniki, Thessaloniki GR 54006, Greece In this work the development and the application of an operational management tool for the Greek Seas is de- scribed. This tool consists of a three-dimensional ¯oating pollutant prediction model coupled with a weather, a hy- drodynamic and a wave model in order to track the movements and the spreading of the pollutants and indi- cate those coastal areas which might be aected. The tool is part of the Poseidon system which has been designed to provide real time data and forecasts for marine environ- mental conditions in the Greek Seas. In this paper, we present four case studies based on realistic scenarios that show the value of the application for long-term strategic planning and short-term decision making in oil spill acci- dents. Ó 2001 Elsevier Science Ltd. All rights reserved. Keywords: chemical pollution; tar balls; ecosystem man- agement; environmental protection; mathematical models; oil spills. Introduction The annual maritime transport of crude oil and re®ned products within the Mediterranean Sea is estimated today at 360 million tonnes corresponding to approxi- mately 20% of the total world oil maritime transport IMO/UNEP, 1998). As a result, an amount varying between 0.5 and 1 million tonnes of oil per year is discharged into the Mediterranean Sea Le Lourd, 1977). The continual release of oil into the sea from marine operations and land-based activities is consid- ered to be a source of contamination more important than accidents involving large-scale oil spills in the sea UNEP, 1988). Nevertheless, over the last 15 years more than 55 000 tonnes of oil have been spilled in the Mediterranean resulting from 242 accidents reported to the Regional Centre IMO/UNEP, 1998). In the same period more than 12 major oil accidents have been re- ported from the Aegean and Ionian Seas while more recently a persistent tar contamination has been ob- served along the northern and western coasts of the island of Crete Kornilios et al., 1998). In addition tar deposition has recently increased in many coastal areas of the south-west Aegean and the south-east Ionian Sea. While shipments of early Azeri oil to the world markets through the Turkish Straits and the Aegean have already commenced, the recent discovery of large deposits of oil and natural gas in Azerbaijan, Kazakh- stan and Turkmenistan is expected to increase the oil maritime trac through the Aegean. The result could be an even higher risk of oil pollution, both intentional and accidental, and it is therefore in the interests of Greece and Turkey, to protect their coastal zones on which they largely depend for tourism and other human activities. Spill simulation models are increasingly used to pro- vide preventive measures and to assess risks, and gen- erally to assist the development of strategies for oil spill contingency planning and response in the event of an accidental oil spill in the sea Volckaert and Tombro, 1989). In this paper the Poseidon pollutants transport model PPTM) is described. It is a fully operational model, which eciently simulates drift, spreading and weathering of ¯oating chemicals, taking into account major physical and chemical processes. The application of the model in four areas of strategic interest with re- spect to present and future oil production and trans- portation as well as its sensitivity in the prediction of oil spill movement and impacts related to oil spill accidents is also presented. The model may be used either in hindcast mode for the tracing of the source of a spill, or in a forecast mode in order to predict the path, the MarinePollutionBulletin Vol. 43, Nos. 7±12, pp. 270±278, 2001 Ó 2001 Elsevier Science Ltd. All rights reserved Printed in Great Britain 0025-326X/01 $ - see front matter PII: S0025-326X01)00080-7 *Corresponding author. Tel.: +30-81-346-860 ext. 152; fax: +30-81- 241-882. E-mail address: ank@imbc.gr P. Annika). 1 Tel.: +30-1-9946161. 2 Tel.: +30-31-995601. 270