Impact of wind forcing on surface transport in the Gulf of Naples

In this work, we use the high-resolution Campania Regional Ocean Model (CROM) forced with four modelled wind fields provided by different weather prediction systems (ERA5, SKIRON, WRF, and MOLOCH), to assess their performance in driving simulations of the Lagrangian surface transport in the Gulf of Naples. The simulated wind fields are first compared with the locally observed dataset recorded by the ISPRA weather station. The observed paths of four CARTHE drifters, released in the Bay of Naples in July and September 2021, are then compared with the simulated trajectories of virtual particles. The latter are obtained exploiting the current velocity field provided by CROM, forced with the above-mentioned wind products, as input of a Lagrangian particle tracking tool (TRACE). The accuracy of the simulations is quantified by adopting the Normalized Cumulative Lagrangian Separation Distance metrics. Our findings indicate that SKIRON attains the best score in most of the analyzed scenarios, particularly under weak wind conditions. However, in operational scenarios where wind accuracy cannot be assessed in advance, the use of a multi-source trajectory - averaging simulated drifts from different model configurations - provides a more robust solution. This multi-model approach helps to minimize errors that could arise from relying on a single wind product. Finally, considering the different wind forcings, significant differences were found both in surface exchange between two subregions of the Gulf of Naples and in the rate of beached particles.