The mapping of the local currents present in Marsaxlokk bay

Abstract

Hydrodynamic models have been integrated into various fields of study due to their ability to predict fluid dynamics. Prior to the digital world, we became accustomed to in the last decade, simulations were mainly carried out using physical hydrodynamic models built-in wave tanks. Nowadays, numerical modelling methods are most of the time implemented. The main goal of this study was to validate the ROSARIO-II SHYFEM model. This is a specific forecasting model that was specifically set up for the waters surrounding the Maltese Islands. This implementation builds on the SHYFEM model. In particular, the sea surface temperature, the sea surface current magnitude, and the sea surface current direction parameters were validated through the use of in-situ and ex-situ data. Actual measurements were obtained by using a pair of Coastal Nomad MT drifters. This was done at Marsaxlokk Bay, an area situated in the southern part of Malta. The ex-situ information consisted of two datasets derived from two different models; one from the ROSARIO-II SHYFEM model, the other one from the Copernicus Mediterranean Sea Physics Analysis and Forecast model, a regular grid coarser model that runs over a larger domain and that is available through the Marine Copernicus Service. Moreover, wind data from the Marsaxlokk Bay area was derived from a meteo station that is installed on the breakwater within the same location. While the focus of the study was specifically on the ROSARIO-II SHYFEM model, the Copernicus model dataset was used in tandem with the in-situ drifter data. These were also correlated with the wind. The accuracy of the ex-situ data was established by making use of comparative statistical analysis. The results derived for the three tested parameters varied. While the modelled sea surface temperature was found to be very accurate, the forecasted sea surface current magnitude and direction were less than ideal.