The world’s oceans have been studied and monitored for many decades to enhance our understanding. In today’s world, with the explosion of new data provided by many different Earth observation sources and the availability of advanced computing infrastructures (cloud computing, HPC, IoT, Big Data), creating a digital representation of the ocean is becoming a reality. The EC recently funded the H2020 ILIAD project, which aims at establishing an interoperable, data-intensive Digital Twin of the Ocean (DTO). The ILIAD DTO will integrate real-time sensing of ocean variables, state-of-the-art high-resolution models, modern data analytics and digital infrastructures to create virtual representations of physical processes and understand their behaviour, anticipating and predicting their response to simulated events and future changes. ILIAD will enable an ecosystem of interoperable DTOs, integrating the plethora of existing EU Earth Observing and Modelling Digital Infrastructures. It will fuse a large volume of diverse data and will enhance ocean data infrastructures with additional observation technologies and citizen science.  ILIAD will provide a virtual environment representing the ocean, capable of running predictive management scenarios and will utilize Big Data analytics for forecasting of spatiotemporal events and pattern recognition. Several DT pilots will be undertaken in several key thematic areas such as offshore wind energy, wave and tidal energy, biodiversity assessments, marine pollution and more. 

The current work presents ongoing activities for a coastal, high-resolution Digital Twin pilot for Cretan Sea, to be demonstrated in the frame of ILIAD project. The pilot focuses on oil spill pollution monitoring and forecasting. The DT environment combines high-resolution forecasting services based on numerical weather (WRF), hydrodynamic (NEMO), sea state (WAVEWATCH III) and particle tracking models (MEDSLIK-II), enhanced by the integration of  Sentinel data and real-time observations from novel, low cost current and waves meters, drifting trackers, as well as citizen science. WRF model is applied for forecasting of meteorological variables at  ̴ 3 km resolution by dynamic downscaling of coarser resolution climatic modelling forecast data (NOAA’s GFS). This way, higher computational accuracy is achieved over Cretan Sea, thus revealing finer wind scales phenomena. The downscaled weather forecasting data are used to force NEMO and WAVEWATCH III, to obtain high-resolution forecasts of important marine parameters, such as sea currents, temperature, salinity and waves over a fine grid of   ̴ 1 km for the coastal area of Crete. For oil spills, the DT of Cretan Sea will integrate operational analysis of Sentine-1 images, triggering MEDSLIK-II oil spill model once an oil spill event or anomaly is identified. Adjusting forecasts to observations by reinitialising the model with updated observational patterns will contribute to the forecast error growth being implicitly accounted for and minimized. The pilot DT virtual environment will allow on-demand simulations of predictive scenarios of oil spill events and response strategies.  

The aim of the Digital Twin is to aid the immediate response in case of accidental oil releases, minimize the damage and reduce the time for environmental recovery.

Acknowledgement: This research has received funding from the European Union’s H2020 RIA programme under GA No 101037643.

How to cite: Spanoudaki, K., Kozyrakis, G., Metheniti, V., Parasyris, A., and Kampanis, N.: The Cretan Sea oil spill Digital Twin pilot for the ILIAD Digital Twin of the Ocean, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11561, https://doi.org/10.5194/egusphere-egu23-11561, 2023.

Oil spills in the marine field can have serious consequences for ecosystems, the environment, public health, the economy, and communities. Thus, following the spillage of 12,000 tons of crude oil from the fuel tanks of the Baniyas power plant in summer 2021, daily operational oil spill predictions were carried out  to predict the spill transport and fate in the Levantine basin, Eastern Mediterranean, supporting the Regional Marine Pollution Emergency Response Centre for the Mediterranean  (REMPEC) and national response agencies. High frequency met-ocean forecasting data from the Copernicus Marine Monitoring Service (CMEMS), the European Centre for Medium-Range Weather Forecasts (ECMWF), and regional models (SKIRON, CYCOFOS) were used, along with satellite-derived SAR data from EMSA-CSN and optical images from ESA to initiate the oil spill models and to determine the evolution, the extent and coverage of the spillages. Two up-to-date and advanced Lagrangian particle-tracking models, OpenDrift and MEDSLIK were used to assess and evaluate the oil spill predictions, generated by the aforementioned models, under a variety of met-ocean forcings and configurations, indicating the significant role of the high-resolution met-ocean data in the evolution of the oil spill trajectory. A number of quantitative metrics were used to evaluate the ability to adequately reproduce the oil spill spreading, by comparing the SAR observed oil spillages against the models results, in more detail.

How to cite: Keramea, P., Kokkos, N., Zodiatis, G., Sylaios, G., Coppini, G., Peña, J., Benjumeda Herreros, P., Sepp-Neves, A. A., Lardner, R., Liubartseva, S., Soloviev, D., Scuro, M., Nicolaidis, A., and Viola, F.: Oil spill modeling assessment of the 2021 Syrian oil spill using SAR imagery and multi-forcing forecasts, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-1573, https://doi.org/10.5194/egusphere-egu23-1573, 2023.

In the present work, we focus on chronic oil pollution from ships since even small amount of toxic oil compounds has immediate adverse biological effects. Moreover, routinely released hydrocarbons tend to cumulatively exceed volumes of the largest historical oil spills.

We perform stochastic simulations of virtual oil spills from ships in the Adriatic 2017–2020 applying the EMODnet vessel densities as a proxy for starting locations. MEDSLIK-II oil spill model is run using the high resolution (1/24 degree) currents and sea surface temperature provided by the Copernicus Marine Service and the ECMWF winds with a horizontal resolution of 1/8 degree.

Chronic exposure to operational oil spills is reported in terms of hazard indices for 5 vessel groups: (1) the pleasure and passenger ships that comprise ~47.2% of the total number of ships in the model domain; (2) cargo and service vessels with a contribution of ~24.2%; (3) fishing fleet with ~21.5%; (4) tankers with ~5.9%; and (5) remaining ships with ~1.2%.

The highest hazard indices from all ships are found in the northernmost part of the basin and along the coastlines of Italy, Croatia, and Slovenia. Near several major ports (Trieste, Koper, Venice, Split, Rijeka, Pescara, Brindisi, Durres, Zadar, Šibenik, and Dubrovnik), they are also elevated at the sea surface and on the coastlines. Conversely, the southern Adriatic exhibited the lowest values of hazard indices.

Comparative analysis of the integrals over the territorial waters of Italy and Croatia shows that the Croatian coastal waters are more chronically polluted than the Italian ones, despite their host less ships than the coastal waters of Italy. The reason for such an inconsistency is probably related to the differences in efficiency of circulation when the pollution from ships quickly dissipates along the Italia coast and tends to stagnate near the Croatian coast. Cargo and service ships are identified to be the main polluters in the Italian coastal waters. While in the Croatian coastal waters, most of the oil is received from the pleasure and passenger ships, particularly, from coastwise shipping. Offshore waters are found to be significantly less polluted than the coastal ones, with the main contribution from fishing, cargo and service vessels.

The results obtained can be considered representative of future events since the vessel density distribution and the amount of oil operationally spilled are assumed to be typical of the present state and not to change dramatically in the future. The historical meteo-oceanographic datasets 2017–2020 used are supposed to correspond to a realistic sample of possible weather and sea state conditions. The hazard indices computed can be used to improve the strategy of satellite and aerial surveillance, in-situ sampling, and ecotoxicological research in the Adriatic.

The presentation summarizes the results obtained in the framework of the FIRESPILL Project (Fostering Improved Reaction of cross-border Emergency Services and Prevention Increasing safety LeveL) funded under the Interreg V-A Italy-Croatia CBC 2014–2020 Programme (AP2–Security and Resilience).

How to cite: Liubartseva, S., Coppini, G., Verdiani, G., Mungari, T., Ronco, F., Pinto, M., Pastore, G., and Lecci, R.: Modeling the operational oil spills from shipping in the Adriatic Sea, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2235, https://doi.org/10.5194/egusphere-egu23-2235, 2023.

The world's oceans are confronted with plastic pollution, 80% of which is of terrestrial origin, flowing mainly from the mismanaged waste of coastal populations and to a less extent, from river discharge. To study the fate of this pollution, we follow the trajectories of neutral plastic particles released continuously in numerical ocean simulations with two realistic source scenarios defined according to poorly managed waste from coastal populations and river discharge. The trajectories are three-dimensional and calculated for a period of 24 years by the Ariane Lagrangian tool from ocean currents simulated by a ¼° global ocean general circulation model (NEMO). The important particularity of the present model is that it is coupled with the WaveWatch III (WW3) wave model and consequently represents the Stokes drift in a consistent manner. The results are compared to trajectories calculated with an uncoupled NEMO simulation in which the Stokes drift is simply not considered. The results show that microplastics (as neutral particles) accumulate at the surface in the subtropical convergence zones of the Ekman transport before penetrating to depth and being strongly dispersed around 200 to 300 m depth over 40 degrees of latitude. At the end of the simulation, about 5.3% of the microplastics remains at the surface in these convergence zones and near the emission regions for the wave-coupled model, whereas only 2% remains for the uncoupled model. Our results indicate that waves may increase the retention of neutral plastic particles at the surface by a factor of two to three because of the upward vertical velocities induced by the divergence of Stokes transport in the surface layers. Plastic surface concentrations are maximal in the North Pacific and Indian Ocean basins. This result is due to the large discharge fluxes surrounding these basins of the northern hemisphere. The Mediterranean Sea exhibits also highly concentrations in microplastics due to high coastal population densities. This work shows the strong influence of waves (and Stokes drift) on the transport of plastic particles in the oceans, both on the retention of particles at the surface, the importance and location of convergence zones, and on the dispersion of neutral plastics at depth.

How to cite: Huck, T., Bajon, R., Grima, N., Maes, C., Blanke, B., Richon, C., and Couvelard, X.: Influence of waves on the three-dimensional distribution of plastic in the ocean, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-13780, https://doi.org/10.5194/egusphere-egu23-13780, 2023.

Marine microplastics are a global environmental issue. However, there are still large data and knowledge gaps in microplastics from sea-based sources. One of the concerned sea-based microplastic sources is ships' greywater discharge. Greywater generated from galley, laundries, showers, and washbasins in a ship can be discharged directly to the sea without treatment. In this study, we present the sampling approach of greywater and information about the abundance and characteristics of microplastics. To our knowledge, it is the first attempt to determine microplastic abundance and characteristics in ships' greywater according to its use categories (galley, laundry and shower, and cabin washbasin). Greywater samples were collected from three different holding tanks (tanks A, B, and C) at R/V Onnuri of Korea Institute of Ocean Science and Technology (KIOST). To enable the sample collection, the discharge system was converted to manual discharge and an additional pump and valve were installed on the pipeline connected to each tank. Greywater was sampled when the vessel was at anchor (1^st sample) and during the research cruise (2^nd sample). For the 1^st sample, a grab sampling was conducted and for the 2^nd sample, samples were collected at 5-day intervals. Semi-automated FTIR analysis was conducted for microplastic identification. During the analysis, fiber bundles composed of polyester (PES) and polypropylene (PP) were detected. Bundles were counted as one individual particle or composing particles were counted individually, if possible. The highest microplastic abundance was found in tank C from the laundry and shower room in which a large number of microfibers such as PES fibers were detected. The average microplastic abundances were 149,660±77,574 n/m³ (62,000–209,600 n/m³) in 1^st sample and 135,563±87,141 n/m³ (75,000–177,667 n/m³) in 2^nd sample. The microplastic abundances were similar and this can be attributed to the fact that people use the ship's facilities where greywater can be generated even while at anchor. In addition, not only the generation of microplastics but also greywater could be large during navigation. Though the microplastic abundances were similar in 1^st and 2^nd samples, a greater variety of polymers were detected in 2^nd sample (25 types) than in 1^st sample (15 types). Polymers used in paint were also highly detected in the 2^nd sample (8%) than in the 1^st sample (2%). This might be due to more diverse activities took place on the deck and inside the ship during the research activity than when at anchor. Fibers were more dominant in 2^nd sample (66%) than in 1^st sample (25%). This may be because more people use washing machines while sailing than at anchor. In addition, since many cabins are occupied during the research cruise than when at anchor, washing in cabins and fibers detached from fabrics from people’s activity during navigation might have contributed to relatively higher PES fiber composition in 2^nd sample. The results of this study would be useful in understanding the sea-based microplastic pollution through ship’s greywater, and for estimation of the microplastic emission from ships to the marine environment.

How to cite: Jeong, J., Jang, Y. L., Eo, S., Hong, S. H., and Shim, W. J.: Occurrence and Characteristics of Microplastics in in a Ship’s Greywater According to Usage Patterns, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10694, https://doi.org/10.5194/egusphere-egu23-10694, 2023.

Marine plastic pollution is one of the most visible environmental problems in and around the coastal regions of South East Asia. To fully address the marine plastic pollution problem, there must be a source-to-sink approach, reducing litter at each stage of its pathway to the open ocean. Mangroves are an important and widespread ecosystem in South East Asia on the interface between terrestrial and marine environments, and a key habitat and nursery for a number of species. Mangroves have also been reported to trap plastic litter, potentially acting as secondary sources to coastal marine environments. The Philippines are particularly vulnerable to compound hydrological events due to the seasonal monsoon and typhoons which regularly cross the region. South East Asia is a complex region oceanographically and hydrologically with high loads of plastic litter being exported into the regional seas. To correctly estimate local plastic pollution budgets and understand the transboundary movement of plastic from land to sea, modelling studies must account for the different environmental drivers and strong seasonality of the region. 

Here, we present preliminary results of a modelling study investigating the impact of Typhoon Rai on the retention and contribution of plastic litter by mangrove ecosystems of Cebu Island, the Philippines. The results of a three-dimensional, hydrodynamic model (ROMS) with wind, tidal and wave forcing will be presented. Future plans to apply a Lagrangian particle tracking model informed by in-situ measurements to investigate the behaviour of plastic litter within this typhoon weather system will also be outlined. 

This will help to understand how plastic litter is retained or exported during extreme events around Cebu Island and assess the likelihood of mangroves to act like a temporary sink or secondary source during extreme and mean events. Understanding the role of mangroves under different environmental conditions could clarify another step in the source-pathway-sink model of plastic litter in the region. 

How to cite: Reed, B., Robins, P., Demmer, J., and Neill, S.: Do mangroves act as a secondary source of plastic during extreme events?, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-13936, https://doi.org/10.5194/egusphere-egu23-13936, 2023.

Over the last ten years, satellite imagery has become one of the most effective means to observe offshore oil spills, especially over a large area, thanks to their high spatial resolution and wide swath coverage. In particular, the use of images acquired by multi-sensors, including Synthetic Aperture Radar (SAR), optical, and visible/near-infrared, allows not only to early and quickly detect oil spills but also to monitor oil drift in short-terms (several hours) and long-terms (one or two days). Such approach has not been assessed in-depth in previous studies probably due to the lack of satellite data. A case study was presented in [1] to observe the movement of oil slicks through the combination of data acquired by SAR satellites, SAR airborne system, optical instrument, and in-situ observations. However, it is very complicated to implement such method for the other cases of oil spills since it requires many different platforms and sensors that are not systematically available. Therefore, this paper focuses uniquely on the collocation of sequential images acquired by various satellite sensors (SAR and optical) for oil drift monitoring in short-terms (several hours) and long-terms (up to 24–36 hours).

For instance, to observe oil spills caused by a wrecked ship offshore Corsica (France) in Oct. 2018, we combine the images acquired by Sentinel-1 SAR (Oct. 8, 2018, 05:27:57 UTC, 17:21:45 UTC; Oct. 9, 2018, 17:14:27 UTC), Sentinel-2 optical sensor (Oct. 9, 2018, 10:20:21 UTC), and Radarsat-2 SAR (Oct. 9, 2018, 04:04:15 UTC). The techniques of oil spill detection from SAR and optical images are different. They are based on an advanced image processing procedure that will be presented at the conference. Due to the time lags between these images, we can estimate the movement of the detected oil slicks in terms of distance, velocity, and direction for 6, 12, 24, 36 hours of observation. Finally, we compare the oil drift results with the hourly data of met-ocean variables (surface wind and current) to assess the impact of the latter on oil drift. Surface wind fields (0.25° × 0.25° grid) and current vectors (0.083° × 0.083° grid) are extracted from the ERA-5 [2] and CMEMS [3] reanalysis data, respectively.

[1] C. Brekke, M. M. Espeseth, K.-F. Dagestad, J. Röhrs, L. R. Hole, and A. Reigber, “Integrated analysis of multisensor datasets and oil drift simulations—a free-floating oil experiment in the open ocean,” J. of Geophysical Research: Oceans, vol. 126, e2020JC016499, 2021, doi: 10.1029/2020JC016499.

[2] H. Hersbach et al., “ERA5 hourly data on single levels from 1959 to present,” Copernicus Climate Change Service (C3S) Climate Data Store (CDS). (Accessed on <05-12-2022>), 10.24381/cds.adbb2d47, 2018.

[3] Global Ocean 1/12° Physics Analysis and Forecast updated Daily (Accessed on <05-12-2022>), doi: 10.48670/moi-00016.

How to cite: La, T. V., Pelich, R.-M., Chini, M., Li, Y., and Matgen, P.: Making use of multi-sensor satellite imagery for oil spill observation and oil drift monitoring, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2815, https://doi.org/10.5194/egusphere-egu23-2815, 2023.

How to cite: Alendal, G., Blackford, J., Carpentier, S., Dankel, D. J., Dewar, M., El Droubi, S., Fagerås, B., Gasda, S. E., Olyenik, A., Omar, A., Pawar, R., Romanak, K., Snee, D., Schütz, S. E., and Torabi, P.: Assurance offshore CO2 monitoring, a cross-disciplinary approach., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15119, https://doi.org/10.5194/egusphere-egu23-15119, 2023.

In this study, we conduct numerical simulations to investigate the transport and accumulation of microplastics (MPs) in the Gulf of Finland (eastern Baltic Sea). The transport of MPs is simulated using a Lagrangian particle tracking model, developed by the authors, which accounts for the physical transport and transformational processes specific to MPs, such as diffusion, beaching, resuspension, and biofouling.

Positively and negatively buoyant particles were included to represent different types of MPs. High-resolution (250 m) 3D hydrodynamic and biogeochemical model data are used as input to the MPs model. Major rivers and wastewater treatment plants around the Gulf of Finland are the sources of MPs in the model.

The main objectives of the study are 1) to perform a sensitivity analysis of four processes (beaching, mixing, resuspension, and biofouling) to investigate the importance of each process on the distribution of MPs in the Gulf of Finland; and 2) to execute a multi-year simulation using realistic MPs input to locate the main accumulation areas in sediments and beaches around the Gulf of Finland.

Results of the initial sensitivity analysis indicate that the changes in the parametrization of beaching have a stronger effect on the horizontal distribution of MPs in off-shore sediments than the changes in the parametrization of resuspension. The maximum MPs concentration is observed near the sea surface; however, MPs have also spread into the water column.

How to cite: Siht, E., Mishra, A., Väli, G., Buhhalko, N., Liblik, T., and Lips, U.: Modeling the transport and accumulation of microplastics in the Gulf of Finland, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15139, https://doi.org/10.5194/egusphere-egu23-15139, 2023.

Plastic is recognized as a threat to marine ecosystems and estimating the level of plastic and microplastics (MP) pollution of the World Ocean is nowadays the goal of many studies. However, the use of different methods for sampling and analysis of MPs leads to the problem of comparing the results obtained. Studies on surface MP pollution of the surface sea water are based on the application of the manta or neuston nets that collect water from the upper 10-20 cm layer (the “surface” MP) or submersible pumping systems, that collect water from the water layer 3-5 m below the sea surface (the “subsurface” MP). These two techniques allow to collect particles of different size fraction, i.e. >300 µm for the surface MP and >100 µm for subsurface MP. The aim of this work was to study the distribution of surface and subsurface MPs and to reveal an influence of oceanographic conditions on their spatial distribution as an example of the open ocean waters of the Central Atlantic and coastal water in Norwegian fjords. It was shown that microplastics found in the surface and subsurface layers differ not only in the size of the items found, but also in morphology, types of polymers, abundance, weight concentration and their spatial distribution. Different hydrodynamic processes affect the fate of plastic occurring exactly at the sea surface and several meters deeper. MPs inhabiting the subsurface waters (about 3-5 m depth) have buoyancy close to neutral and appear to be suspended in the surface mixed layer and are readily transported from the sources to the distant regions by ocean currents. Subsurface turbulence is probably the main process that maintains the MPs in the near-surface part of the water column. In contrast, the surface MPs (which are captured by sampling with surface nets) have positive buoyancy and its spatial distribution is significantly influenced by water dynamics, wind and waves, which led to a more scattered distribution on the ocean surface. It was shown that surface and subsurface microplastics differ significantly in a number of properties and, apparently, they should be considered as two independent groups that may have different sources, and their distribution is driven by different hydrophysical processes. Thus, MPs data collected using both methods simultaneously could provide additional information about MPs fate in the ocean.

How to cite: Pakhomova, S., Zhdanov, I., Berezina, A., and Yakushev, E.: Difference in the fate of surface and subsurface microplastics: an example for open and coastal waters, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16273, https://doi.org/10.5194/egusphere-egu23-16273, 2023.