Search

An experiment, carried out in the Middle Adriatic in late May 2017, documented the existence of a dense water dome in the area between the island of Blitvenica (close to the east coast) and the island of Jabuka (in the open sea). The yo-yo CTD measurements showed that the dome center was located at a distance of about 20 km from the coast while the vmADCP measurements revealed that the surface circulation around the dome was cyclonic. The temperature above the dome was slightly lower than farther off, as documented by in situ and remotely-sensed data. At the same time, a decrease of temperature close to the east coast was documented by bottom probes and satellite images. The meteorological data and modeling results showed that during the May 2017 experiment the northern winds prevailed, implying that the observations could be interpreted in terms of simultaneous occurrence of open-sea and coastal upwelling. With the aim of verifying the interpretation, a number of schematized numerical experiments were conducted. To begin with, the modelled wind fields were decomposed into the curl and curl-free components by using the Helmholtz-Hodge decomposition. Subsequently, the components were used to impose the forcing on the Adriatic model, assuming flat bottom and realistic bathymetry. The simulations showed that the wind curl was responsible for the occurrence of open-sea upwelling whereas the curl-free wind component supported the development of coastal upwelling., The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)

Five oceanographic cruises were organized from 2017 to 2021 to explore occurrence of upwelling and downwelling in the eastern part of Middle Adriatic. Four cruises took place in late May or early June whereas the 2020 cruise was in August. High-resolution, yo-yo CTD profiling together with ship-borne ADCP measurements were performed along a vertical cross-section over the Middle Adriatic Pit. Wind fields were obtained from operational meteorological model ALADIN. The strongest upwelling, both coastal and open-sea, was observed in 2017 after several days of strong, upwelling favorable NNW winds, also characterized by a significant positive curl. In 2018, under mild, nearly curl-free NW winds, the pycnocline was almost flat, slightly rising in the vicinity of coast, whereas in 2019 moderate sirocco with negative curl produced strong downwelling in the area stretching about ~30 km from the coast. Measurements in 2020 were performed twice, one day apart; in a strongly stratified sea with no offshore wind-curl, only coastal upwelling was observed as an almost linear rise of the pycnocline. First measurement in 2021 was done after two days of strong NW wind turning to strong sirocco, the second followed two days later. The two passes revealed a complex wave-like structure of the pycnocline (variability of ~15 m in the vertical and ~35 km in the horizontal direction). Hydrodynamic model ROMS is used to reproduce and interpret the empirical findings. The open-sea upwelling in the eastern Middle Adriatic occurs when a significant positive-curl wind blows for several days over moderately stratified sea., The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)

The 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., peer-reviewed

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 implementation of this integrated HFR regional network., This study has been partially developed in the framework of the Interreg MED Strategic Project SHAREMED, co-financed by the European Regional Development Fund under the funding program Interreg MED 2014–2020. Website: https://sharemed.interreg-med.eu/ (last access: 31 March 2022). We are also grateful for the partial support of the (i) the project PO FEAMP 2014/2020 (Misura 2.51) funded by Regione Campania (Italy), (ii) the 2017 PRIN project EMME (Exploring the fate of Mediterranean microplastic: from distribution pathways to biological effects) funded by the Italian Ministry for Research (grant agreement no. 2017WERYZP), and (iii) the CMEMS-INSTAC phase II, which provides the context of the activities for HFR data harmonization, standardization, and distribution. Collaborative discussion on data management harmonization at the European level has also been carried out thanks to the contribution of the projects INCREASE (CMEMS Service Evolution Call for Tenders 21-SE-CALL1) and SeaDataCloud (EU-H2020 GA no. 730960).