# A System to Improve Port Navigation Safety and Its Use in Italian Harbours
###### Abstract  
This article describes research aimed at developing a system able to support local authorities and port communities in optimizing port navigation, avoiding or managing critical situations induced by sea-level variations in harbours and minimizing environmental damages and economic losses. In the Mediterranean basin, sea-level changes are mostly due to astronomical tides, related to the gravitational attraction between Earth, Moon and Sun. Nevertheless, sea-level variations are also influenced by meteorological tides, which are geodetic adjustments of sea surface due to atmospheric pressure variations above a water basin. So, starting from monitoring or forecasting environmental parameters in harbours, the system updates port bathymetric maps based on sea-level variations (acquired in the past, measured in real-time, or expected in the future) and detects hazardous areas for a certain ship moving inside a port at a given moment, by means of the implementation of \"virtual traffic lights\". The system was tested on some real situations, including the analysis of maritime accidents (stranding of ships), providing satisfactory results by correctly signalling potentially dangerous areas variable over time. The architecture of the system and results achieved using it in the ports of Livorno and Bari, in Italy, are herewith described. coastal maritime transport; maritime safety; ship accident prevention; harbour waterside management; environmental monitoring; marine environment protection +
Footnote †: journal: Applied Sciences  
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Footnote 1: email: {M.S. atmospheric pressure trends to estimate future sea-level changes named meteorological tides, which have to be added to the astronomical ones, that are periodic and well-known, to obtain the expected sea level and then the future real bathymetric map of a port. In fact, the slow up-down motion of sea level in Mediterranean coastal areas is essentially due to tides that are mainly the sum of astronomical components (in particular the diurnal and the semidiurnal ones) due to gravitational attraction between Earth, Moon and Sun, and then periodic, well-known (through harmonic analysis) and foreseeable for each location by means of tide charts [21]. In addition to them, an important role in determining tidal fluctuations can be played by meteorological components (due to atmospheric pressure perturbations), in particular, if they occur along with the astronomical ones. During the last ten years, \"anomalous\" tidal oscillations have been observed along Italian coasts. In particular, a meteorological tide (also named \"meteo-tide\") is a geodetic adjustment of the sea surface resulting from a perturbation of atmospheric weight above a water basin (up and down sea level motion that compensates the Newtonian unbalance): an increase in atmospheric loading induces an outcoming seawater flux (low tide), while a decrease in atmospheric weight causes an incoming flux (high tide); therefore, sea level lowers with an atmospheric pressure rise, and rises with a pressure fall. This phenomenon depends on a lot of variables (e.g., the topography of the basin) so, unlike the previous phenomenon, it is not describable by a deterministic law: the statistical correlation between changes of atmospheric pressure (cause) and sea-level variations (effect) is estimated by analysing meteorological events (sea-level changes consequent to atmospheric pressure variations) that occur in a certain location for a long time interval. Once this correlation (named hydro-barometric transfer factor) is known, meteorological tides can be forecasted starting from the knowledge of atmospheric pressure variations [22; 23; 24; 25; 26; 27; 28; 29; 30]. Finally, once astronomical and meteorological tides are both known, the expected global variation of sea level can be estimated as the algebraic sum of the two contributions and then passed as input to the software application that performs the updating of the bathymetry. Here.