Simulation of plastic particles in the Western Mediterranean Sea

In this Thesis we simulate the dispersion of 60000 particles starting from the 3rd of October, 2020, immediately after a strong storm (Storm Alex) hit the area, causing the flooding of the two rivers and diffused damage across Europe. We carry out our work by running numerical simulations of sea surface currents with the Western Mediterranean Operational Model (WMOP), developed by the Balearic Islands Coastal Ocean Observing and Forecasting System (SOCIB). We will also perform simulations using the Copernicus Marine Environment Monitoring Service-Monitoring Forecasting Centre (CMEMSMED MFC), the outputs from the two models, which have a different spatial resolution (∼2 km for the WMOP and ∼4.5 km for the CMEMS-MED MFC), will be then compared to look for similarities and differences in the results. We are interested in investigating how the particles disperse and where is their final position (on water, beached, or out of domain), and in which country. To filter out small-scale turbulence from the models outputs we perform four different types of simulations, with three-hourly outputs, in the WMED domain. The reference simulation is the output of the model, containing all the features representable by the model. We then make a temporal average of the currents (second simulation), a 50 km running average of the models currents (third simulation), and compute geostrophic currents from values of sea surface height (fourth simulation), from both models. The propagation of plastic is then simulated with these four currents. We learn that the role of the turbulence is that of keeping the material from reaching the North Balearic Front (NBC), the materials is slowed down and diffused in the total currents simulation, whereas in the three filtered simulations we observe extensive beaching in the geostrophic simulation, and on-water propagation in the temporal and spatial averages.