Leopoldo Fazioli

A high-resolution real-time forecasting system for predicting the fate of oil spills in the Strait of Bonifacio (western Mediterranean Sea).

The Strait of Bonifacio is a long and narrow area between Corsica and Sardinia. To manage environmental emergencies related to the spill of oil from vessels, an innovative forecasting system was developed. This tool is capable of operationally predicting the dispersion of hydrocarbon spills in the coastal area of the Bonifacio Strait, either from an instantaneous or continuous spill and either in forward or backward mode. Experimental datasets, including ADCP water current measurements and the trajectories of drifter buoys released in the area, were used to evaluate the accuracy of this system. A comparison between the simulation results and experimental data revealed that both the water circulation and the surface transport processes are accurately reproduced by the model. The overall accuracy of the system in reproducing the transport of an oil spill at sea was estimated for both forward and backward prediction mode and in relation to different forecasting time lags.

Assessment of oil slick hazard and risk at vulnerable coastal sites.

This work gives an assessment of the hazard faced by Sicily coasts regarding potential offshore surface oil spill events and provides a risk assessment for Sites of Community Importance (SCI) and Special Protection Areas (SPA). A lagrangian module, coupled with a high resolution finite element three dimensional hydrodynamic model, was used to track the ensemble of a large number of surface trajectories followed by particles released over 6 selected areas located inside the Sicily Channel. The analysis was carried out under multiple scenarios of meteorological conditions. Oil evaporation, oil weathering, and shore stranding are also considered. Seasonal hazard maps for different stranding times and seasonal risk maps were then produced for the whole Sicilian coastline. The results highlight that depending on the meteo-marine conditions, particles can reach different areas of the Sicily coast, including its northern side, and illustrate how impacts can be greatly reduced through prompt implementation of mitigation strategies.

A relocatable ocean model in support of environmental emergencies

During the Costa Concordia emergency case, regional, subregional, and relocatable ocean models have been used together with the oil spill model, MEDSLIK-II, to provide ocean currents forecasts, possible oil spill scenarios, and drifters trajectories simulations. The models results together with the evaluation of their performances are presented in this paper. In particular, we focused this work on the implementation of the Interactive Relocatable Nested Ocean Model (IRENOM), based on the Harvard Ocean Prediction System (HOPS), for the Costa Concordia emergency and on its validation using drifters released in the area of the accident. It is shown that thanks to the capability of improving easily and quickly its configuration, the IRENOM results are of greater accuracy than the results achieved using regional or subregional model products. The model topography, and to the initialization procedures, and the horizontal resolution are the key model settings to be configured. Furthermore, the IRENOM currents and the MEDSLIK-II simulated trajectories showed to be sensitive to the spatial resolution of the meteorological fields used, providing higher prediction skills with higher resolution wind forcing.

The regional forecasting systems of the Italian seas

ABSTRACT Over the last 15 years, five operational systems for the forecasting of the circulation of the Italian seas have been developed, which provide products of use for the management and safety of marine activities and for the protection of the marine environment. The first systems which focused on the Adriatic Sea and the Sicily Strait, have been added to over the years, to cover the Tyrrhenian Sea, the seas around Sardinia, and, finally, the region around the Bonifacio Strait, a small area interested by an intense marine traffic. In this work, the main features of the five regional systems are described and examples are given of their capabilities and their use for revealing new features of marine circulation.

Effects of protection rules and measures in an important international strait area: the Bonifacio Strait

The Strait of Bonifacio, between Sardinia and Corsica, is an area with environmental characteristics of great importance and uniqueness in the Mediterranean. Since the early ‘90s Italy and France have been trying to preserve the area through the creation of national and international marine parks, activating understandings to limit the danger of environmental emergencies and ensuring compliance with international agreements, both from the EC and IMO. The bilateral agreement of 1993 prohibits the passage through the Strait of Italian and French tankers and other ships with hazardous and noxious substances at full load, but it does not restrict the transit of ships from other countries or when empty. The analysis of 2000–2009 data of transits through the Strait of Bonifacio, derived from the Vessel Traffic Service provided by the Coast Guard of La Maddalena, shows the fulfilment of agreements within this maritime sector and their limits, and possible remedies are suggested.

Impact of different initialisation methods on the quality of sea forecasts for the Sicily Channel

ABSTRACT An operational ocean forecasting system provided numerical predictions on the main hydrodynamics in the seas around Sicily. The system is evaluated using an independent dataset of sea surface temperature (SST) satellite observations. A set of specific numerical experiments are carried and the simulated SST data was compared with the satellite data observed at selected dates. Two kinds of initialisation techniques are adopted to generate different initial conditions: ‘slave mode’ and ‘partially active mode’. The accuracy of both approaches is analysed to individuate the optimal nesting strategy. The results show that the partially active mode improves the forecasts, resulting in a model accuracy increase of up to about 30%.