Model-based insights into pathways and fate of oil spills in the Mediterranean Sea

To better understand the potential consequences of future oil spill accidents in the Mediterranean Sea, extensive Monte Carlo simulations were performed using the Lagrangian oil spill model MEDSLIK-II. Stratified sampling was based on the hypothetical distribution of oil spill sources linked to the latest observational inventory of oil slicks. The transport of virtual oil spills was forced by currents and winds provided by the Copernicus Marine Service and ECMWF from 2018 to 2021. The processing of over two million virtual spill statistics provided practical information for contingency, offshore oil production perspectives, and ecosystem protection. Oil pollution hazard indices, expressed in probabilistic terms, were mapped on the sea surface and coastlines. Arrival times and the percentage of beached oil were defined, computed, and represented through their probability distributions. The Aegean Sea coastline was found to be the most impacted area, with high coastal hazard indices, short arrival times with a median value of approximately 3.1 days, and significant beached oil fractions of around 30 %. In contrast, the Ionian Sea, Central Mediterranean, and Levantine Sea showed relatively low hazard indices, longer arrival times, and smaller beached oil percentages, due to the high dissipative properties of these subbasins. These hazard indices could be incorporated into a multi-hazard assessment and aid in risk assessments. The arrival time and beached oil fraction statistics could be used to plan the development of offshore oil production fields and to minimize the risks of maritime oil transfer activities.