Yaiza Samper

The water quality in port domains is highly dependent on the capacity for renewal and mixing with external water. This study uses Lagrangian modelling to investigate renewal time in Barcelona, Tarragona, and Gijón harbours (Spain), which represent semi-enclosed micro-tidal and meso-tidal environments. For this purpose, different particle-tracking simulations have been carried out in each of the ports to study the trends of circulation and water renewal trends both on the surface layer and at the bottom. The results indicate that in microtidal Mediterranean ports, the renewal time is longer at the bottom (32 days in Barcelona and 61 days in Tarragona). Conversely, in the mesotidal port of Gijón, located on the Cantabrian coast, the opposite pattern is observed, with higher renewal times at the surface (14 days). While the results from Lagrangian modelling exhibit magnitudes comparable to in situ measurements from previous studies, it remains essential to evaluate the specific characteristics of each method and compare these findings with other similar works.

In this paper, we use observations and numerical simulations to investigate the effect of meteorological parameters such as atmospheric pressure and wind on harbours water exchanges. Knowing these water exchanges is of vital importance to care for and improve the environmental health of the harbor water and its surrounding areas. This knowledge requires an analysis of different meteorological and hydrodynamic parameters from detailed and high definition studies. SAMOA (System of Meteorological and Oceanographic Support for Port Authorities) is a project developed by Puertos de Estado (PdE) in collaboration with several Spanish harbour authorities and Universities to provide enhanced meteorological and oceanographic information and services for harbour operations. In the framework of this project, the Maritime Engineering Laboratory (LIM/UPC) has developed a high-resolution numerical model for the forecasting ocean variables at coastal and harbour scales. The effectiveness of this model to reproduce the hydrodynamics in the ports is evaluated using meteo-oceanographic observations from different measurement campaigns during 2020 2021, and 2022 carried out in the ports. Firstly, this article analyses and validates the results of the SAMOA meteo-oceanographic prediction system in the ports of Huelva, Gijón and Cartagena (mesotidal and microtidal environments) and, secondly, based on the analysis of observations, it proposes the numerical analysis of different events with high renewal times. The data includes information on atmospheric pressure, wind, sea level and currents parameters. These variables are validated by visual matching of the time series of modelled data and observations, as well as by statistical analyses and correlations between model results and measurements.

In this study, we use observations and numerical simulations to investigate the effect of meteorological parameters such as wind and atmospheric pressure on harbour water exchanges. The modelled information is obtained from the SAMOA (Sistema de Apoyo Meteorológico y Oceanográfico de la Autoridad Portuaria) forecasting system, which is a high-resolution numerical model for coastal and port-scale forecasting. Based on the observations, six events with high renewal times have been proposed for analysis using the SAMOA model. Therefore, the conclusions of this study have been possible due to the combination of observed data from the measurement campaigns and the information provided by the model. The results show that days with higher renewal times coincide with favourable wind-direction events or increases in atmospheric pressure. After analysing these events using model results, it was observed that during these episodes, water inflows were generated, and in some cases, there was a negative difference in levels between inside and outside the harbour produced by atmospheric pressure variations. The latter may be due to the fact that the water in the harbour (having a lower volume) descends faster and, therefore, generates a difference in level between the exterior and the interior and, consequently, inflow currents that imply an increase in the renewal time. These results are a demonstration of how meteorological information (normally available in ports) can be used to estimate currents and water exchanges between ports and their outer harbour area.

Mediterranean ports feature complex layouts and exert important environmental pressures in squeezed coastal zones. They experience mild meteo-oceanographic conditions during part of the year, leading to water velocities that are close to the resolution limits of observation equipment. The paper addresses the challenge of characterising summer port hydrodynamics by designing intensive field campaigns, focused on hydrodynamic variables, such as harbour entrance fluxes. The approach was developed for three Spanish microtidal harbours with different domain sizes and one or two entrances. These elements play a key role in harbour exchanges through the entrance and the subsequent water renovation. The paper will present and discuss the meteocean data and inferred variables, such as renovation times, which is a key indicator of water quality. From this basis, the paper will discuss the changing estuarine circulation patterns and the role of upwelling and downwelling on observed water temperature peaks. The conclusions will address the role of harbour hydrodynamics in integrated coastal water quality and port engineering, particularly for ports’ environmental impacts on adjacent beaches. To assess the full hydrodynamic domain, forecasting models are helpful. The continuous observations presented in this work would also help in the implementation and validation of these models.

Quality ocean information from observations and forecasting is crucial to support evidence-based decision making and providing a crucial framework for underpinning the scientific basis for policies that regulate the use of the oceans, coastal regions and port areas, maintaining their healthy ecosystems, protecting the development of the littoral zones, and monitoring the environmental mitigation efforts. However, there are fundamental gaps in our ocean observing and forecasting capabilities, limiting our capacity to manage the oceans, coastal regions, and port areas sustainably. Therefore, particularly for coastal areas, it is necessary to ensure high-level integration for coordinated observations that can be sustained in the long term and help to improve ocean forecasting to ensure safe and sustainable human-coastal interaction.The EuroSea initiative [1] is an innovative action of the European Union that brings together key European actors in ocean observation and forecasting with key European end-users in ocean observation, thereby promoting a genuinely interdisciplinary ocean observing system and providing oceanographic products and services. Furthermore, it enables high-resolution coastal operations and forecasting systems in restricted domains such as local ports, beaches, and nearby coastal waters. The EuroSea Project aims to advance scientific knowledge about ocean climate, marine ecosystems, and their vulnerability to human impacts and demonstrate the ocean's importance for a healthy and economically viable society.Within the EuroSea project framework, we present a 3D hydrodynamic tool to improve the sustainable management of Barcelona's local coastal waters. We use the Coupled Ocean-Atmosphere-Wave-Sediment Transport Modeling System [2] that utilises the Model Coupling Toolkit to exchange prognostic variables between the circulation model ROMS and the wave model SWAN. As part of the system, the wave and circulation models run with nested and refined grids to provide increased spatial resolution, scaling down to solve nearshore wave-driven flows, all within selected regions of a larger, coarser-scale coastal modelling system. Bathymetry was built using a combination of data from EMODnet [3] and specific high-resolution sources provided by local authorities. Copernicus products have driven these high-resolution simulations.Field campaigns have been used to validate results, displaying agreements between modelled outputs and in-situ observations. Therefore, the model provides results that will be used to develop new forecast capabilities, such as predicting erosion and flooding, simulating rip currents, tracking the floating debris, and knowing the flushing times.Finally, we look ahead to the future of the development and maintenance of the operational prediction systems because their harmonisation and integration with the existing ocean knowledge will increase the availability of credible scientific evidence to inform industry, help to reduce the impact of human activities on the ocean and improve environmental management. We would like to acknowledge financial support from EuroSea Project (GA862626), an EU Innovation Action funded through Horizon 2020. [1] EuroSea Project (https://eurosea.eu/)[2] Warner, J.C., Armstrong, B., He, R., and Zambon, J.B., 2010, Development of a Coupled Ocean-Atmosphere-Wave-Sediment Transport (COAWST) modelling system: Ocean Modeling, v. 35, no. 3, p. 230-244.[3] EMODnet (https://www.emodnet-bathymetry.eu/)

This paper analyses the summer water circulation in Barcelona, Tarragona and Castellón harbours (east and north-east of Spain), based on field data acquired between April and September 2019. These data include information of wind, waves, 1DV currents, temperature and salinity parameters. The research characterizes the hydrodynamics at the mouth of each harbour and allows to estimate circulation patterns according to its physical characteristics. The availability of simultaneous data on the three harbours allows to analyse and study possible differences. The results show a two-layer circulation in all the harbours. In the cases of Tarragona and Castellón, both with a single mouth, the surface layer flows out of the harbour and the bottom currents circulate inwards. This pattern is reversed in the Barcelona harbour, which has two mouths and is more influenced by the local winds, affecting the distribution of currents in the water column. The bottom water temperature reveals significative differences between the three harbours, especially during the first half of the summer. The results suggest that sea level effects and the water exchange between the harbour and open-sea strongly determine the bottom water temperature. Nevertheless, the sea level series are different in the three harbours. In Barcelona and Tarragona, the meteorological tides are more affected by the atmospheric pressure changes; however, in the case of Castellón, which is smaller, the main influence is associated with the wind, which displaces water and causes a convergence when finding land that results in an increase in sea level. Therefore, the results reveal the importance of knowing the dimensions and morphology of each harbour to describe correctly its hydrodynamics because, despite being under comparable climatic conditions due to their geographical proximity, different hydrodynamic responses are observed to similar atmospheric forcings. The low intensities of the currents and the geometric complexity of the harbour domains, compared to open waters, imply that operational forecasting in these domains can present considerable uncertainties if they are not combined with field data.