Sea Storm Analysis: Evaluation of Multiannual Wave Parameters Retrieved from HF Radar and Wave Model

Intense atmospheric disturbances, which impact directly on the sea surface causing a significant increase in wave height and sometimes strong storm surges, have become increasingly frequent in recent years in the Mediterranean Sea, producing extreme concern in highly populated coastal areas, such as the Gulf of Naples (Western Mediterranean Sea, Central Tyrrhenian Sea). In this work, fifty-six months of wave parameters retrieved by an HF radar network are integrated with numerical outputs to analyze the seasonality of extreme events in the study area and to investigate the performance of HF radars while increasing their distances from the coast. The model employed is the MWM (Mediterranean Wind-Wave Model), providing a wind-wave dataset based on numerical models (the hindcast approach) and implemented in the study area with a 0.03° spatial resolution. The integration and comparison with the MWM dataset, carried out using wave parameters and spectral information, allowed us to analyze the availability and accuracy of HF sampling during the investigated period. The statistical comparisons highlight agreement between the model and the HF radars during episodes of sea storms. The results confirm the potential of HF radar systems as long-term monitoring observation platforms, and allow us to give further indications on the seasonality of sea storms under different meteorological conditions and on their energy content in semi-enclosed coastal areas, such as the Gulf of Naples

Coastal high-frequency radars in the Mediterranean ??? Part 1: Status of operations and a framework for future development

Due to the semi-enclosed nature of the Mediterranean Sea, natural disasters and anthropogenic activities impose stronger pressures on its coastal ecosystems than in any other sea of the world.With the aim of responding adequately to science priorities and societal challenges, littoral waters must be effectively monitored with high-frequency radar (HFR) systems. This land-based remote sensing technology can provide, in near-real time, fine-resolution maps of the surface circulation over broad coastal areas, along with reliable directional wave and wind information. The main goal of this work is to showcase the current status of the Mediterranean HFR network and the future roadmap for orchestrated actions. Ongoing collaborative efforts and recent progress of this regional alliance are not only described but also connected with other European initiatives and global frameworks, highlighting the advantages of this cost-effective instrument for the multi-parameter monitoring of the sea state. Coordinated endeavors between HFR operators from different multi-disciplinary institutions are mandatory to reach a mature stage at both national and regional levels, striving to do the following: (i) harmonize deployment and maintenance practices; (ii) standardize data, metadata, and quality control procedures; (iii) centralize data management, visualization, and access platforms; and (iv) develop practical applications of societal benefit that can be used for strategic planning and informed decision-making in the Mediterranean marine environment. Such fit-for-purpose applications can serve for search and rescue operations, safe vessel navigation, tracking of marine pollutants, the monitoring of extreme events, the investigation of transport processes, and the connectivity between offshore waters and coastal ecosystems. Finally, future prospects within the Mediterranean framework are discussed along with a wealth of socioeconomic, technical, and scientific challenges to be faced during the implementatio

Coastal high-frequency radars in the Mediterranean ??? Part 2: Applications in support of science priorities and societal needs

International audienceThe Mediterranean Sea is a prominent climate-change hot spot, with many socioeconomically vital coastal areas being the most vulnerable targets for maritime safety, diverse met-ocean hazards and marine pollution. Providing an unprecedented spatial and temporal resolution at wide coastal areas, high-frequency radars (HFRs) have been steadily gaining recognition as an effective land-based remote sensing technology for continuous monitoring of the surface circulation, increasingly waves and occasionally winds. HFR measurements have boosted the thorough scientific knowledge of coastal processes, also fostering a broad range of applications, which has promoted their integration in coastal ocean observing systems worldwide, with more than half of the European sites located in the Mediterranean coastal areas. In this work, we present a review of existing HFR data multidisciplinary science-based applications in the Mediterranean Sea, primarily focused on meeting end-user and science-driven requirements, addressing regional challenges in three main topics: (i) maritime safety, (ii) extreme hazards and (iii) environmental transport process. Additionally, the HFR observing and monitoring regional capabilities in the Mediterranean coastal areas required to underpin the underlying science and the further development of applications are also analyzed. The outcome of this assessment has allowed us to provide a set of recommendations for future improvement prospects to maximize the contribution to extending science-based HFR products into societally relevant downstream services to support blue growth in the Mediterranean coastal areas, helping to meet the UN's Decade of Ocean Science for Sustainable Development and the EU's Green Deal goals

Numerical-ecotoxicological approach to assess potential risk associated with oilfield production chemicals discharged into the sea

Several different chemical products are used on oil platforms to aid oil-water separation during the production process. These chemicals may enter into the sea by means of production water (PW), the main discharge derived from oil and gas offshore platforms. Consequently, toxic effects may occur in the marine environment, causing reductions in wildlife numbers, degrading ecosystem functions and threatening human health. For most of these chemicals, environmental toxicity and safety thresholds in marine ecosystems have not been fully investigated as yet. In this work, a numerical-ecotoxicological approach is proposed to assess the potential environmental risk associated with the discharge of five oilfield production chemicals (deoiler, scale inhibitor, corrosion inhibitor, catalyst, dehydrating agent) from a platform in the southern Adriatic Sea (Mediterranean Sea). Their concentrations in the seawater are numerically predicted, under different seasonal conditions, starting from the real concentrations used during the production process. The predicted concentrations are then evaluated in terms of possible toxic effects in order to assess the potential risk of oilfield production chemicals discharged into the sea

An Integrated Reconstruction of the Multiannual Wave Pattern in the Gulf of Naples (South-Eastern Tyrrhenian Sea, Western Mediterranean Sea)

Surface gravity waves retrieved by a network of HF (High Frequency) radars and measured in situ by an ADCP (Acoustic Doppler Current Profiler) current meter connected to an elastic beacon were used to carry out a multiple-year characterization of the wave field of the Gulf of Naples (south-eastern Tyrrhenian Sea, western Mediterranean). The aim of the work was to create a climatology of the study area and to demonstrate the potential of an integrated platform for coastal studies. The patterns recorded by the different instruments were in agreement with the wave climatology of the southern Tyrrhenian Sea as well as with previous scores for the same area. The results presented in this work also highlight seasonal and interannual consistency in the wave patterns for each site. In a wider context, this study demonstrates the potential of HF radars as long-term monitoring tools of the wave field in coastal basins, and supports the development of integrated observatories to address large-scale scientific challenges such as coastal ocean dynamics and the impact of global change on the local dynamics

Backward reconstruction of plankton sources in the Gulf of Naples

The Gulf of Naples (GoN) is a coastal area of the Southern Tyrrhenian Sea representing a very complex system, influenced by numerous interacting factors depending on the peculiar physical and biogeochemical conditions of this area. Since 2004 a system of HF coastal radars (Sea Sonde CODAR) operates in the GoN providing real time (hourly data) surface current fields with a resolution of 1.0 × 1.0 Km over almost the entire area of the GoN. Moreover plankton abundance in the GoN is monitored weekly at the Long-Term Ecological Research station MareChiara (LTER-MC) since 1984. An oscillating population dynamics, with an alternation, especially in summer, between phases reflecting the coastal and offshore influence on the biological community, has been frequently observed at LTER-MC station. Such an opportunity to integrate biological data and current measurements at high spatio - temporal resolution, makes the GoN a natural laboratory to investigate the role of surface circulation in structuring the marine plankton community. The results here presented refer to a year-long analysis carried out for 2009, which was characterized by a very accurate estimate of the surface dynamics, with a reduced number of HF radar data gaps. A Lagrangian particle transport model, forced by the HF radar current fields, has been applied to identify probable sources and transport pathways of plankton at LTER-MC station. In particular a backward-trajectory modeling approach has been used to reconstruct a probability distribution function around the LTER-MC station. The results from the backward trajectory simulations allowed to identify origin of plankton observed at LTER-MC; the surface dynamics analysis accounted for the relationship between the inter-annual alternation in the plankton community and the variability in the wind-driven circulation

Hydrology and Dynamics in the Gulf of Naples during Spring of 2016: In Situ and Model Data

The hydrology and circulation in the northwestern part of the Gulf of Naples are analyzed during the transition period from spring to summer (April–June) 2016 through numerical simulations and in situ observations. The simulations were performed with the high-resolution sigma-coordinate Campania Regional Ocean Model (CROM) encompassing the wider Campania coastal system. Temperature, salinity and density were measured at the Long Term Ecological Research Program Mare-Chiara sampling site located two miles from the coast, while current intensity and direction were measured in situ by an acoustic Doppler current profiler connected to an elastic beacon anchored at a short distance from the city of Naples. The modeled circulation scenarios and the marine hydrology provided by the model on a regular grid allow interpreting the observational data during the selected period. In turn, the model-data comparison clarifies the model performance in reproducing the nearshore marine dynamics, which goes beyond the actual model resolution

Characterizing the coastal dynamics behaviour within the Gulf of Naples using modelling, HF radar and in situ measurements

The integration of numerical models in coastal observatories represents a current challenge for the scientific community, constituting a frontier both for research purposes and for a variety of practical applications, ranging from coastal protection to search and rescue activities, or support to engineering works and operational structures. Here we present the monitoring network installed in the Gulf of Naples, our recent advances in coastal and in-situ observations and the integrated ocean-atmosphere modelling approach, through connections to the state of the art and still opened research issues that will be the challenges for the next years. Currently, the monitoring network of the Gulf of Naples is composed of moored instrumentation and a HF radar system composed of three antennas that provide hourly data of surface currents for the entire Gulf at a spatial resolution of 1 km. The ocean model configuration is a ROMS (Regional Ocean Modeling System)-based code, configured on the region (~13-15E, 40-42N). The increasing availability of long-term observations, the large dataset recently acquired in sea-truth campaigns and numerical output from meteorological and ocean models allow us to use these integrated tools to characterize the coastal dynamics processes, and thus provide quantitative support to decision makers in the field of management strategy on oil spill and search and rescue operations, vulnerability of coasts and correct management strategies of the environmental heritage. This talk presents diverse scientific issues recently addressed by the DiSAm (University of Naples Parthenope) in the broad activity of developing and tuning of the oceanic components of modeling system. We will show some numerical model results in the Gulf of Naples basin in response to high resolution atmospheric forcing provided by the SKIRON model focusing mainly on the seasonal circulation and on the mesoscale and submesoscale variability associated with the current system of the basin. A particular attention is devoted to the analysis of the fate of waters originated inside the Gulf and in the Tyrrhenian Sea, which circulate in the area, giving insights as to the water renewal mechanisms of individual subareas. The results of simulations are compared with eulerian synoptic measurements of surface currents provided by the HF radar system installed on the Gulf's coasts, showing a very good agreement between the two data sets