Orals: Tue, 5 May, 14:00–15:45 | Room L2
Due to the large amounts of brackish water in estuaries produced by mixing of fresh river discharge and salty ocean water, mixing is one major characteristic of what is an estuary. Mixing can be quantified locally as well as on estuary-wide scales. Diagnostics of integrated mixing are given for estuarine volumes bounded by transects as well as isohalines (surfaces of constant salinity) moving with the flow. It can be shown how entrainment across a moving isohaline surface depends on gradients of turbulent salt flux and mixing per salinity class. Various relations are derived that link estuarine salt mixing to other estuarine properties such as the freshwater discharge and the bulk estuarine circulation. For estuaries bounded towards the ocean by a fixed transect, the Knudsen mixing law can be derived, where estuarine mixing is the product of the Knudsen salinities of inflowing and outflowing water masses and the river discharge. Major processes that drive estuarine mixing are acting on various time scales (tidal, fortnightly, weather and discharge time scales) and spatial scales (channel-shoal interaction, mixing fronts). I will review major aspects of estuarine mixing. As underlying methods for the quantification of mixing, observational concepts, as well as numerical modelling methods such as consistent turbulence closure modelling and numerical mixing analyses are sketched. Future perspectives are outlined.
How to cite: Burchard, H.: Estuarine Mixing, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-23121, https://doi.org/10.5194/egusphere-egu26-23121, 2026.
Compound flooding and drought events are becoming increasingly frequent and intense across many catchment areas draining into the Mediterranean basin. The interconnected nature of catchment hydrology and marine hydrodynamics processes poses significant challenges to advancing the numerical modelling of the catchment-sea continuum systems and to provide a comprehensive representation of the complex response of deltas to the climate extremes. To address these challenges, we used a seamless numerical modelling of the river-sea continum based on a Finite Element code (SHYFEM-MPI – Micaletto et al. (2022), Verri et al. (2023)). The SHYFEM-MPI experimental settings has been progressively refined with generalized vertical coordinates and wet and dry capabilities, aiming at deepening the understanding of compound flooding and drought events occurring in the Po Delta system, which is Italy's longest river and the second-largest freshwater source for the Mediterranean basin. Therefore, a four-year experiment (2019–2023) was conducted to simulate significant events, including the November 2019 storm surge and river flood event and the July 2022 record breaking drought. Model findings were validated against available in-situ and satellite observations allowing a detailed tracking of the salt wedge intrusion length during the compound extremes. Based on the results obtained, we explored the role of non-linear combination of multi-scale and cross-scale forcing mechanisms to enhance the modeling accuracy and the understanding of the complex physical processes underlying such extreme events.
How to cite: Kaiser, J., Verri, G., Worou, L., Viola, F., Piermattei1, V., and Pinardi, N.: The complex response of the river-sea continuum systems to the climate extremes: insights from the Po delta, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-19709, https://doi.org/10.5194/egusphere-egu26-19709, 2026.
The Neretva River is the largest river in the eastern part of the Adriatic basin with a total length of 218 km, of which only about 20 km are in Croatia. Saltwater intrusions into the Neretva River estuary have numerous negative impacts on agricultural production, freshwater resources, biodiversity and the balance of this fragile ecosystem. Therefore, understanding this phenomenon is important not only from scientific and ecological perspectives, but also for economic reasons. Unfortunately, the problem of salinization is expected to become even more severe in the future under projected climate change with rising sea level and decreased river discharge in summer. In this study, the dynamic nature of saltwater intrusions into the Neretva River estuary was analysed using long-term CTD (conductivity, temperature, and depth) measurements carried out monthly over a wide area of the estuary, as well as measurements conducted between March 2023 and 2024, but with higher spatial and temporal resolutions along the Croatian part of the Neretva River course. The long-term measurements were carried out at five marine CTD stations positioned in the close vicinity of the river mouth, while a sixth station was located within the Neretva River. Temperature and salinity profiles mainly influenced by heat and water air-sea fluxes and river discharge revealed seasonal changes in the spread of low-salinity river-influenced water. The recent high-resolution measurements included CTD profiles collected during six field cruises and continuous CTD, total oxygen, water pressure, water level, and meteorological measurements at selected locations along the watercourse. The CTD vertical profiles were collected at 13-19 quasi-evenly distributed stations from the river mouth to the town of Metković and revealed several characteristic patterns of the sea wedge’s intrusion. During the cold part of the year, with moderately high river discharge, saltwater intrusion was limited to the lower part of the estuary, spreading in the bottom layer over relatively short distances of up to 6 km from the river mouth. In contrast, summer conditions characterised by low river discharge allowed saltwater to spread over 20 km from the river mouth up to the town of Metković. An extreme event occurred in mid-May 2023 following a strong cyclonic disturbance accompanied by heavy rainfall. Detailed CTD measurements along the Neretva River course showed that low-salinity water occupied the entire water column, from the city of Metković to the river mouth. The strong Neretva River outflow (discharge of over 1400 m3/s) completely flushed the saltwater out of the river, resulting in near-homogeneous salinity profiles with values below 0.3. In addition to field cruises, autonomous CTD and total oxygen loggers were deployed at four locations along the course of the river, while meteorological and hydrological conditions were monitored by an automatic station located in the port of Metković. Overall, analysis of the collected data showed that saltwater intrusions are mainly influenced by river discharge, but also by weather conditions, tides, and human activities.
How to cite: Beg Paklar, G., Mihanović, H., Džoić, T., Dunić, N., Udovičić, D., and Muslim, S.: Saltwater intrusions into the Neretva River estuary: long-term measurements and selected case-studies , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-11972, https://doi.org/10.5194/egusphere-egu26-11972, 2026.
Submarine canyons are recognised hotspots of enhanced vertical exchange and complex circulation, yet their role in modulating the seasonal energy cycle between mean and turbulent flows remains poorly understood. This study reveals that Cape Canyon, a major topographic feature in the Southern Benguela Upwelling System (SBUS), exhibits a seasonal reversal in its dominant energy pathway, shifting from a net sink of eddy kinetic energy (EKE) in summer to a net source in winter.
Using a high-resolution (1-km) CROCO simulation, we diagnose instability mechanisms and energy pathways via the eddy-to-mean kinetic energy conversion rate, C. During austral summer (DJF), the strong, stratified Benguela Jet interacts with canyon topography to form coherent, high potential vorticity (PV) vortices. However, the canyon region is a net EKE sink (C < 0). Across 88.3% of the canyon area, energy is transferred from eddies to the mean flow, indicating suppression of eddy growth despite the presence of organised vortices.
In the austral winter (JJA), the sign of C reverses. The canyon becomes a net EKE source (C > 0), with 50.1% of the canyon area exhibiting mean to eddy energy transfer. This transition is consistent with a shift from summer damping of coherent vortices to wintertime barotropic and baroclinic instability of a weakened mean flow. Concurrently, dynamical hotspots shift from surface-intensified (0 to 100 m) in summer to deep-reaching (900 to 1000 m) in winter, co-located with enhanced vertical motion and indications of convective mixing.
Spatially, the response is asymmetric. The northern flank becomes the primary winter instability hotspot (55.5% source area), transitioning from a summer anticyclonic vortex street to a more diffuse eddy generating regime. In contrast, the southern flank remains a persistent, strain-dominated dissipative zone throughout the year, acting as a dynamical barrier.
These seasonal energy pathways likely have biogeochemical consequences. Summer damping may favour retention, whereas wintertime eddy generation and deeper-reaching mixing may enhance nutrient supply from intermediate waters (SAMW, AAIW), potentially preconditioning the system for the spring bloom. Overall, Cape Canyon functions as a seasonal energy switch that modulates cross-shelf exchange and biogeochemical connectivity in the SBUS, with broader implications for the impacts of submarine canyons in Eastern Boundary Current Systems.
How to cite: Ragoasha, M., Cambon, G., Mashifane, T., Ghomsi, F., Rapolaki, R., and Herbette, S.: Submarine Canyon Modulation of Eddy Kinetic Energy: A Seasonal Regime Shift in the Southern Benguela, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-12022, https://doi.org/10.5194/egusphere-egu26-12022, 2026.
Trace elements are essential micronutrients for marine primary production, playing key roles in a variety of metabolic processes. This study investigated the biogeochemical cycling and benthic fluxes of Mn, Fe, Co, Ni, Cu, Zn, and Cd in the two contrasting marginal seas of the northwestern Pacific, East/Japan Sea and Yellow Sea. Rare earth element fractionations ([Nd/Er]PAAS and Ce/Ce* ratios) were used to trace scavenging and water mass inputs.
In the East/Japan Sea, trace element distributions were grouped into three categories. Mn, Fe, and Co were influenced by atmospheric deposition in surface waters and benthic input in the bottom layer, with fluxes of 742, 96, and 0.8 μmol m-2 yr-1, respectively. Ni and Cu showed a depletion from surface waters and a limited influence from benthic inputs. The distributions of Zn and Cd were more strongly regulated by biological activity. On top of that, an unusual decoupling between the concentrations of Zn and SiO44- was discovered in this study. Zn correlated positively with SiO44- in the upper 500 m but negatively at greater depths, likely owing to shelf inputs. In the Yellow Sea, all trace elements exhibited a vertically conserved distribution owing to rapid water mixing.
These results contribute to the current biogeochemical understanding of the region by providing higher-resolution cross-transect investigations and report the decoupling of Zn–SiO44- in the East/Japan Sea for the first time.
How to cite: Chen, X., Kim, I., and Jeong, H.: Boundary Exchange and Benthic Fluxes Drive Trace Element Cycling in North Pacific Marginal Seas, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-6223, https://doi.org/10.5194/egusphere-egu26-6223, 2026.
The northern Adriatic Sea, due to the discharge from the Po and other rivers, can be described as a region of freshwater influence (ROFI). Together with fluvial inflows, other defining features are the strong atmospheric forcing, mainly Bora and Sirocco wind regimes, and tidal motions, most noticeably in peripheral environments such as the Venice Lagoon.
These elements contribute in shaping the vertical structure of the water column and the in making the northern Adriatic basin one of the dense water formation sites in the Mediterranean Sea. Furthermore, vertical processes such as stratification contribute in defining horizontal dynamics, for example Rossby radius of deformation variability, therefore affecting the mesoscale dynamical field.
Here we investigate and characterise the mesoscale variability of the northern Adriatic basin via numerical experiments, and assess how different vertical grid discretisations and turbulence parametrisations can affect it, using the MITgcm numerical ocean model.
We run a series of numerical experiments: a first batch of tests on periodic boundary “boxes”, to evaluate different mixing schemes and vertical grids; then, we select a subset of four among these setups and use them to run 5-year long simulations of the northern Adriatic hydrodynamics.
We find that increased vertical resolution results in better agreement with temperature and salinity observations, both remotely sensed (satellite SST) and sampled in situ (temperature and salinity profiles). As regards the vertical mixing shemes, GGL outperforms KPP, at times independently of the resolution under consideration.
By studying the mesoscale dynamical field we find that the Rossby radius of deformation responds mainly to the change in vertical grid resolution rather than to the mixing parametrisations. Instead, the summer stratification improved by the GGL scheme leads to more stable, wider eddies and more variability in the transport of fresh water of riverine origin from the coast towards the open sea, helping explain the observations of lower open sea salinity in summer with respect to winter.
We conclude that turbulent mixing parametrisations in ROFI ocean models can be as important as vertical resolution in determining the overall properties of both the water column and the basin-wide dynamics by shaping the mesoscale range of motion.
How to cite: Giordano, F., Querin, S., and Salon, S.: Effect of vertical grid resolution and mixing schemes on mesoscale dynamics in coastal ocean models: case study in a mid-latitude marginal sea (northern Adriatic Sea), EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-5461, https://doi.org/10.5194/egusphere-egu26-5461, 2026.
The physical dynamics of the Eastern Mediterranean Sea remain challenging to characterize, particularly in the marginal Levantine Sea, where steep continental slopes, narrow shelves, and intense mesoscale and submesoscale activity shape a highly complex coastline. To advance our understanding of circulation in these coastal and shelf environments, we present a new high-resolution regional hydrodynamic model for the Levantine Sea that resolves dominant circulation features, including boundary currents, margin-intensified flows, and dynamically active coastal regions.
Built on the NEMO 3.6 ocean model with a horizontal resolution of 2.2 km and 71 vertical levels, the simulation incorporates realistic atmospheric forcing, river inflows, and carefully tuned open-boundary conditions to ensure physically consistent behaviour over three decades (1992–2022). The model reproduces major seasonal patterns and mixed-layer evolution documented by regional monitoring systems and captures the long-term sea-surface thermal intensification in the basin. Over the 31-year hindcast, temperature trends show a persistent rise in warm anomalies, especially in autumn and winter, consistent with satellite-based assessments of climate-driven heating in the region.
In this study, we emphasize the formation and export of Levantine Intermediate Water (LIW). Beyond the well-established formation in the Rhodes Gyre, the model reveals intermittent intermediate-water production along the continental slopes of the Gulf of Antalya and the Cilician Basin, a feature increasingly recognized by recent research. The extended hindcast further quantifies LIW transport variability through the boundary current, highlighting phases of enhanced outflow, internal recirculation, and quasi-stagnant periods modulated by stratification and wind-driven variability.
The model provides a reproducible platform for investigating circulation processes central to the semi-enclosed Levantine Sea, including boundary-current characteristics, eddy–slope interactions, episodic water-mass formation, and the sensitivity of coastal circulation to atmospheric forcing and long-term thermal changes. It complements regional observational efforts and offers a foundation for future coastal-process studies and operational applications.
How to cite: Serimozu, C., Basdurak, N. B., and Salihoglu, B.: Three Decades of Levantine Sea Dynamics: A High-Resolution Modelling Perspective, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-709, https://doi.org/10.5194/egusphere-egu26-709, 2026.
In multi-centennial integrations of a multilayer shallow-water model of the Mediterranean Sea driven solely by constant volume transports representing Atlantic inflow and intermediate outflow, and with no atmospheric forcing or imposed temporal variability, coherent intrinsic low-frequency fluctuations emerge. These signals propagate predominantly westward at very slow phase speeds, of order 10–30 km/yr, and exhibit horizontal scales of O(100 km). The variability is robust across different dissipation closures and numerical configurations and is most clearly visible at internal density interfaces, particularly in regions of strong bathymetric influence. Comparison with multi-decadal satellite altimetric records reveals significant and spatially coherent correlations in selected areas of the basin, suggesting that the simulated intrinsic variability may contribute to observed sea-level fluctuations. This research is supported by the Italian INVMED-P.R.I.N. project.
How to cite: Rubino, A., Zanchettin, D., Gnesotto, M., Rebronja, A., Fusco, G., Tiede, L., and Pierini, S.: Intrinsic low-frequency variability in long multilayer simulations of the Mediterranean Sea, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-5176, https://doi.org/10.5194/egusphere-egu26-5176, 2026.
In the present study we investigate how the physical properties of mesoscale vortices are affected by and affect characteristics of Intrinsic Oceanic Variability (IOV) in selected areas of the Mediterranean Sea. Using the AVISO Global Mesoscale Eddy Data, we analyze the life-cycles and morphology of vortices in identified IOV hotspots, such as Algerian and Ionian Basins, as well as the northwestern part of the western subbasin, which are known areas where IOV is known to be particularly strong. Specifically, we examine how eddy frequency of occurrence, ellipticity, asymmetry and longevity correlate with simulated regional intrinsic variance. This research is supported by the Italian INVMED-P.R.I.N. project.
How to cite: Rebronja, A., Pierini, S., Zanchettin, D., Gnesotto, M., Fusco, G., Tiede, L., and Rubino, A.: Characteristics of Mediterranean Mesoscale Eddies in Intrinsic Variability Hotspots, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-5450, https://doi.org/10.5194/egusphere-egu26-5450, 2026.
Teleconnections between the North Atlantic and the Baltic Sea region are shaped by the polar jet stream and are critical drivers of weather and climate in the region, thereby impacting the physical and biogeochemical properties of the Baltic Sea ecosystem. This review synthesizes how key circulation features and modes of climate variability, including the North Atlantic Oscillation, atmospheric blocking and the Atlantic Multidecadal Variability, influence the Baltic Sea region. By examining existing literature data and observational and climate model data, we summarize links to temperature, precipitation, storms and other key indicators from synoptic to multidecadal time scales. We then assess how these climate controls cascade into ecosystem relevant processes, namely oxygen dynamics, primary productivity and ocean acidification. Although physical links are already established, the pathways connecting large-scale atmospheric patterns to biogeochemistry are still poorly constrained, partly because dedicated field studies and targeted model experiments are limited. We outline priority research needs to enhance near-term predictability and reduce uncertainty in future projections for the Baltic Sea.
How to cite: Börgel, F. and Ruvalcaba Baroni, I. and the Scientists from the Baltic Sea Region: Teleconnections to the Baltic Sea Region: Controls, Predictability and Consequences, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-4829, https://doi.org/10.5194/egusphere-egu26-4829, 2026.
Posters on site: Mon, 4 May, 14:00–15:45 | Hall X5
How to cite: Ramos-Musalem, K., Mitre-Apáez, A., and Estrada-Allis, S.: Tidal rectification and exchange at the neck of a canyon–bay system: a tides-only modeling framework, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-907, https://doi.org/10.5194/egusphere-egu26-907, 2026.
Under the influence of global warming and human activities, deoxygenation in coastal waters worldwide is intensifying, posing a persistent threat to marine ecosystem health. Deoxygenation events in the Yangtze Estuary and the East China Sea are consequences of the intricate interplay of multiple physical and biogeochemical processes, such as oxygen consumption through organic matter decomposition and oxygen supply via advection or diffusion. In this study, we employ the unstructure-grid hydrodynamic model SCHISM coupled with the biogeochemical model CoSiNE to investigate the direct and indirect effects of hydrodynamic processes, and to reveal the mechanisms of physical-biogeochemical interactions between shelf circulations and coastal pelagic ecosystem on deoxygenation in the East China Sea. The model simulations are used to elucidate the combined influence of the Yangtze River diluted water, the Kuroshio subsurface water, and the Yellow Sea cold water masses and to quantify the key processes driving nutrient and oxygen budgets, which jointly regulate the deoxygenation in the East China Sea. The coupled framework will be used to predict future trends of deoxygenation associated with the projected climate change scenarios.
How to cite: Xu, X. and Xue, H.: Physical-Biogeochemical Coupling Mechanisms of Deoxygenation Events in the East China Sea, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-6148, https://doi.org/10.5194/egusphere-egu26-6148, 2026.
The Elbe estuary located in northern Germany plays a critical role in European maritime trade, primarily through the Port of Hamburg. In this area, however, low-oxygen events i.e., lower dissolved oxygen concentration than expected for an extended period of time, threaten the ecological state and the provision of ecosystem services, especially in summer. Here, we use long-term observations and numerical modelling to analyze the co-occurrence of marine heatwaves i.e., anomalously water warmer than expected for an extended period of time, and low-oxygen events in the tidal Elbe from 2017 to 2024. Statistical analyses reveal a great level of co-occurrence between heatwaves and low-oxygen events specially in spring (31%) and summer (42%).
The degree of co-occurrence varies spatially, with stations downstream of the Port of Hamburg being more susceptible to low-oxygen events during heatwaves. Our model analyses show that mineralization and nitrification increase during spring heatwaves, and primary production also decreases during summer heatwaves, suggesting that different mechanisms act in each season causing low-oxygen events due to heatwaves. Water temperature controls the main oxygen-consuming biogeochemical processes, which are accelerated with warm periods and lead to low oxygen conditions.
How to cite: Purkiani, K. and García-Oliva, O.: Seasonal mechanisms of low-oxygen events in the Elbe estuary, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-14719, https://doi.org/10.5194/egusphere-egu26-14719, 2026.
Multiple long-standing gaps in our understanding of the Arabian/Persian Gulf Outflow (AGO) hinder a detailed characterisation of the AGO as well as an assessment of the impact on the Arabian Sea. These gaps include a lack of systematic AGO thickness budgets, missing observational evidence for detachment thresholds, poorly constrained downstream mixing pathways, insufficient mapping of bathymetric controls on the outflow, sparse data on along-path oxygen modification, and no prior linkage between AGO physical structure and ecosystem, e.g., benthic zonation. Here, we present new high-resolution observational mapping of the AGO thickness, attachment/detachment behaviour, lateral mixing, and benthic changes on the seafloor in the Gulf of Oman, at the mouth of the Arabian Sea. We present seasonal CTD data, combined with high-resolution bathymetry and ROV observations. These data allow us to (1) resolve AGO thickness variability along the margin, (2) identify seafloor attachment and detachment zones, (3) map fine-scale oxygen and pH modification of the outflow, and (4) document changes in marine benthic zonation consistent with AGO boundary-layer structure.
How to cite: Abdelmaksoud, A., Al-Suwaidi, A., and Ali, M.: Shelf turbulence-driven mixing of the Arabian Gulf outflow: Impacts on the Arabian Sea Oxygen Minimum Zone and marine ecosystem, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-6174, https://doi.org/10.5194/egusphere-egu26-6174, 2026.
In situ obsersavations collected by thermosalinographs (TSG) provide valuable information on sea surface temperature (SST) and salinity (SSS) in coastal and shelf regions, where strong spatial gradiants and short-scale variability occur. TSG measurements offer high resolution along survey transects, capturing small scale fluctuations and offers a valuable opportunity for evaluating ocean models and satellite products.
In this study, TSG data aquired during multiple fisheries monitoring surveys from 2019 to 2024 along the Portuguese coast are used to assess the accuracy of SST and SSS fields from the Iberian-Biscay-Irish (IBI) reanlysis, provided by the Copernicus Marine Service, and a dedicated regional CROCO ocean model simulation specifically configured for western iberia. Satellite SST products from the Multiscale Ultrahigh Resolution (MUR) and Mediterranean Sea Ultra High Resolution (MED - UHR) are also compared with in situ observations to examine consistency across observation plataforms. For all surveys, model and satellite data are extracted at the nearest spatial and temporal points matching the TSG measurements processed at the appropriate spatial scales. Statistical skill metrics (bias, correlation coefficient, RMSD, MAE, and Skill score) are applied systematecally across all surveys.
The results show that, although SST is generally well reproduced, SSS displays larger discrepancies in IBI reanalysis, which tends to underestimate nearshore salinity. To improve the representation of nearshore SSS, sensitivity simulations were conducted using the CROCO model with prescribed riverine salinity and daily river discharge. These simulations highlight the importance of ensuring accurate river discharge and salinity values to represent coastal SSS variability and riverine low-salinity plumes along the Portuguese margin.
This evaluatin provides insight into the strengths and limitations of existing models and satellite products, guiding our ongoing efforts to improve our regional simulations of the Ibearin margin and to investigate its physical and biogeochemical processes.
How to cite: Nunes, P., Teles-Machado, A., Moreno, A., Angélico, M. M., Peliz, Á., and B. Oliveira, P.: From Ship to Model: Assessing SST and SSS with TSG Data, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-996, https://doi.org/10.5194/egusphere-egu26-996, 2026.
Offshore floating solar parks are emerging as a promising renewable energy technology, but we still know very little about how they may affect the marine environmental beneath and around them. In particular, their influence on biogeochemical processes such as light availability, primary production, and pelagic and benthic nutrient dynamics remains largely unexplored. In this work, we use a coupled GETM-ERSEM-BFM modeling framework to study the biogeochemical footprint of offshore solar parks. We have developed a 3D nested model system, starting with a regional 5 km resolution model and refining it to a high resolution 500 m domain that focuses on the solar park area. This setup allows us to capture both Rhine plume dynamics and seasonal variability along Dutch coast, while also resolving smaller-scale processes that are important close to the solar parks.
We present first results from the nested model, showing how physical conditions and key biogeochemical variables respond to the presence of floating solar installations. The initial simulations indicate localized changes near the surface, particularly related to light, which in turn influence biological activity. To build confidence in the model setup, we also include preliminary validation by comparing the nested model results with reference simulations and available data. Although these results are still exploratory, they demonstrate the potential of high resolution nested models to investigate environmental effects of offshore solar parks and form a basis for more detailed impact studies in the future.
How to cite: Jr, R. and Van der Molen, J.: Simulating the biogeochemical footprint of offshore solar parks, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-3902, https://doi.org/10.5194/egusphere-egu26-3902, 2026.
In January 2002 the project "Research Platforms in the North and Baltic Sea" (FINO) was initiated by the German Federal Government. Within this project, three research platforms were constructed for long-term, high-resolution monitoring adjacent to planned and operational wind farms. Two of the platforms are located in the North Sea and one in the Baltic Sea. The research platforms have been collecting a comprehensive, multi-parameter dataset comprising oceanographic and meteorological variables. Therefore, these platforms deliver a continuous dataset of environmental measurements before, during and after offshore wind farm construction.
In this contribution, we provide an overview of this long-term dataset, including guidance on its access and usage. The dataset is freely accessible via the data portals of the German Federal Maritime Agency (BSH, Insitu-Portal) and the Copernicus Marine Service (CMS), offering a unique resource for research in climate change, meteorology, oceanography, and renewable energy.
The dataset is widely used for model validation, interdisciplinary research, and operational decision-making by offshore wind farm operators. Its long-term, high-resolution nature makes it particularly valuable for assessing environmental impacts of offshore wind farms and supporting the transition towards sustainable energy.
How to cite: Krohn, L., Cañadillas, B., Deiber, S., Jendersie, F., Lehmann, F., Lutz, D., Lampert, A., Mark, A., Moritz, M., Müller, S., Heiderich, J., Herklotz, K., Harmsen, P., and Stohr, E.: The FINO Dataset: Over20-years of Oceanographic and MeteorologicalMonitoring in Offshore Wind FarmEnvironments, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-20965, https://doi.org/10.5194/egusphere-egu26-20965, 2026.
Recently started the Digital Twin of the Ocean for Offshore Wind Energy (DTO4OWF) project is a 36-month European research and innovation project supporting the sustainable expansion of offshore wind energy in the Baltic and North Seas (BS & NS). According to EMODnet, more than 300 offshore wind farms are planned in EU waters over the incoming decade. This rapid development poses significant challenges related to ecosystem protection and biodiversity conservation, while simultaneously requiring efficient use of wind resources and marine space across multiple temporal scales.
DTO4OWF addresses these challenges through the development of fit-for-purpose, sub-regional Digital Twins of the Ocean (DTOs) that will integrate coupled physical, biogeochemical, ecological, and climate processes. The DTOs will be built using high-resolution, process-based numerical models, constrained by in situ observations, satellite remote sensing, and data assimilation techniques. Machine learning methods are employed to enhance model performance, reduce computational costs, and support scenario-based analyses. The project focuses on five key areas within BS and NS basins, selected to represent contrasting environmental conditions and different stages of offshore wind farm development. For each area, the DTO framework enables the assessment of offshore wind farm impacts across multiple spatial and temporal scales, including short-term operational effects and long-term climate-related changes. The resulting decision-support tools facilitate optimized site selection, safer operations, improved environmental impact assessments, and sustainable marine spatial planning. All applications are designed to be transferable to other European regions and interoperable with EDITO, Destination Earth, and EMODnet infrastructures.
The DTO4OWF consortium consists of 11 partners, and the project leader is Tallinn University of Technology (TalTech, Estonia). The IOPAN contributions focuses on offshore wind farms located in the southern Baltic Sea, with particular emphasis on offshore wind farm–sea ice interactions. The methodological approach is based on high-resolution numerical simulations using the Community Ice CodE (CICE) model, including fast-ice parameterization adapted to shallow, semi-enclosed basin conditions. Model experiments are designed to compare baseline simulations with scenarios including offshore wind farm infrastructure, represented through modified boundary conditions and obstacle-induced ice attachment processes. The simulations are evaluated using available observational data on sea ice extent, thickness, and duration, enabling qualitative and quantitative assessment of wind farm impacts on ice dynamics. This contribution presents the methodological framework, planned sensitivity experiments, and preliminary results illustrating the potential role of offshore wind farms in fast ice formation in the southern Baltic Sea.
Digital Twin of the Ocean for Offshore Wind Energy (DTO4OWE), under the framework of the Sustainable Blue Economy Partnership (SBEP), funded by the National Centre for Research and Development.
How to cite: Jakacki, J., Darecki, M., Muzyka, M., Przyborska, A., Dzierzbicka-Głowacka, L., Dybowski, D., and Janecki, M.: Towards Sub-Regional Digital Twins of the Ocean for Integrated Offshore Wind Energy Impact Studies, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-12804, https://doi.org/10.5194/egusphere-egu26-12804, 2026.
Posters on site: Mon, 4 May, 16:15–18:00 | Hall X5
The NEPTUNE Observatory is a cabled network of seafloor oceanographic instruments in the Northeast Pacific operated by Ocean Networks Canada. Since 2009, there have been many deployments of a Vertical Profiler on the observatory on the upper slope of the continental margin. However there have been many challenges resulting in differing degrees of success and deployment lengths. Currently the profiler is in 400m of water since May of 2024 working on a reduced schedule to help ensure a full annual cycle. Prior to this deployment we’ve had two deployments that survived a significant portion of the year, in addition to shorter deployments.
The placement of the vertical profiler is at 400m depth down the slope of the nominally 200m deep shelf. The slope proceeds down to about 2000m passing a plate subduction zone and meeting the gently sloping Cascadia abyssal plain. The continental slope along the west coast of Canada and the US is heavily excised by canyons and we choose to strategically locate the deployment away from any canyons to remove canyon effects from the observations. Still, the circulation dynamics in the region are very complex. The surface waters are in the transition zone between the wind-driven currents associated with the Alaskan Gyre and California Current Systems. Deeper, the midwater is heavily influenced by the poleward flowing California Undercurrent which is then further modulated by remotely generated passage of coastal trapped waves. Being on the continental slope, the currents are also strongly influenced by the internal tide as well as shorter internal waves generated by the passage of the tides.
The currently deployed Vertical Profiler System (VPS) carries instruments to measure water properties, temperature salinity, oxygen, pCO2, pH, turbidity, fluorescence and upwelling radiance with some redundancy. In this study we put together observations from historic deployments along with the current real-time observations to develop an understanding of the physical coupling with the biogeochemistry, the long-term variability of the water properties as and the interdependencies of these variables. Finally, we delve into the complexities of obtaining water property measurements using this type of vertical profiling system.
How to cite: Mihaly, S., Mellon, S., Bauer, K., and Foloni Neto, H.: Coastal Multidisciplinary Dynamics Elucidated by a Vertical Profiler on the Upper Continental Slope off Vancouver Island, Canada, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-15128, https://doi.org/10.5194/egusphere-egu26-15128, 2026.
Surface ocean currents inferred from satellite altimetry are a key tool for observing large-scale ocean circulation; however, their performance over continental shelves remains challenging due to issues associated with conventional altimetry and global processing strategies. Several recent developments in gridding methods, combined with the increased spatial resolution enabled by the Surface Water Ocean Topography (SWOT) mission, present new opportunities for enhancing current estimates in coastal and continental shelf regions.
In our study, we investigated the mean and seasonal circulation over a 10-year period on the Southwestern Atlantic Continental Shelf using several altimetry-based datasets, including the freely available Copernicus Marine Environment Service (CMEMS) gridded product and newly generated regional datasets specifically adapted to shelf dynamics, as well as output from the GLORYS12v1 numerical model. The resulting circulation patterns are evaluated in the context of previous studies to identify common features and discrepancies among datasets, as well as the influence of recent methodological advances. Differences in the structure and seasonality of the dominant along-shore currents emerge clearly when analyzing cross-shelf transects, partly supplemented by in-situ data from Acoustic Doppler Current Profiler (ADCP) data.
Despite their limited availability to date, we also investigated experimental gridded products that incorporate SWOT observations. Considering the study's findings, the SWOT-induced gridded dataset demonstrates an enhanced ability to resolve small-scale circulation, resulting in higher variability in the ocean currents, and underscores the importance of high-resolution altimetry in representing surface currents over the study region.
How to cite: Passaro, M., Juhl, M., and Dettmering, D.: Surface ocean currents on the Southwestern Atlantic Continental Shelf from Altimetry datasets, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-19560, https://doi.org/10.5194/egusphere-egu26-19560, 2026.
Observations from the global ocean have long confirmed the ubiquity of thermohaline inversions in the upper ocean, often accompanied by a clear signal in biogeochemical properties. Their emergence has been linked to different processes such as double diffusion, mesoscale stirring, frontal subduction, and the recently discussed submesoscale features. This study uses the central Baltic Sea as a natural laboratory to explore the formation of salinity inversions in the thermocline region during summer. We use realistic high-resolution simulations complemented by field observations to identify the dominant generation mechanism and potential hotspots of their emergence. We propose that the strongly stratified thermocline can host distinct salinity minima during summer conditions resulting primarily from the interaction between lateral surface salinity gradients and wind-induced differential advection. Since this is a generic mechanism, such salinity inversions can likely constitute a typical feature of the upper ocean in regions with distinct thermoclines and shallow mixed layers.
How to cite: Chrysagi, E.: Salinity inversions in the thermocline due to wind-induced differential advection, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-4816, https://doi.org/10.5194/egusphere-egu26-4816, 2026.
Salt intrusion is a major problem in deltas globally. Under climate change it is predicted to become a more serious issue. Understanding the source conditions of the saline water entering the estuary is of vital importance. Here we present data from a field campaign carried out around the mouth of the Port of Rotterdam, during the major drought of 2022. Mooring data (velocity, salinity and temperature) deployed around the mouth of the estuary are presented. We explore the changes in the near field plume dynamics during the drought and their connection to the inflowing waters at depth. Our results suggest where the saltier inflowing waters to the estuary are sourced from offshore. We explore how and where mixing of plume waters takes place in the river plume and its impact on lower-layer salinity variation in the nearfield.
How to cite: Pietrzak, J., Wegman, T., Horner Devine, A., Ralston, D., and Kranenburg, W.: Sources of salt Intrusion in a salt wedge estuary under extreme drought conditions, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-21437, https://doi.org/10.5194/egusphere-egu26-21437, 2026.
A new conceptual framework for the assessment of the physical state of the Baltic Sea was introduced recently. The approach is based on the analysis of mutual variability of well-established climate indicators such as basin-wide ocean heat content (OHC) and freshwater content (FWC). Previous studies have reported a positive trend in OHC and a negative trend in FWC. The increase in OHC has been attributed to the rising air temperature over the Baltic Sea, yet the decline in FWC remains largely unexplained. It was noted that neither salt transport to the Baltic Sea, net precipitation, nor total river runoff accounted for the FWC's downward trend. We suggest that more accurate estimates of mass, salt and heat transport between the Baltic Sea and the North Sea are needed, than currently available. This study is designed as the first step towards the goal by analysing model reanalysis data and observations.
The Baltic Sea is a brackish marginal sea connected with the North Sea through the narrow Danish Straits (Øresund, Great Belt and Little Belt) and the Skagerrak and Kattegat transitional zones. A complex geometry and bathymetry of the area complicates the estimation of the transport values using traditional methodology like numerical modelling and solely observation based interpolation methods. We analyse volume, heat and salt transports across sets of transects in Skagerrak/Kattegart transition zone and the southern Baltic Sea using the Baltic Sea Physical Reanalysis data (NEMO, 1 nautical mile resolution, 56 vertical layers, 1993–present). The derived transports are compared to the long-term observational Baltic Saline Inflow (SBI) series.
Our results quantify the consistency and difference in transport between neighbouring model’s transects over the transition zone between the North Sea and Baltic Sea. They show comparable temporal variability between area-mean model transports and the SBI index and spectral analysis indicates that the reanalysis captures the dominant temporal scales of inflow variability, while differences in amplitude suggest sensitivity to area choice.
We develop purpose specific data-driven models to link these two data sources into mass, heat and salt exchange estimators for the North Sea and Baltic Sea connective area, using attention-based Transformer architectures to learn the time-dependent relationships between reanalysis predictors and available observations, and to estimate volume, heat, and salt exchange through the North Sea–Baltic Sea gateway.
How to cite: Nemeth, P. and Raudsepp, U.: Towards limiting uncertainties in the estimates of mass, salt and heat transport between the Baltic Sea and the North Sea, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-12277, https://doi.org/10.5194/egusphere-egu26-12277, 2026.
Field-based monitoring of coastal morphology requires high costs and is often constrained to calm wave conditions, which limits operational frequency. As a result, despite high spatial resolution, conventional surveys typically suffer from low temporal resolution. To improve temporal resolution between discrete surveys, we developed a satellite-based framework to estimate intermediate morphological changes by tracking crescentic nearshore sandbar (CNSB) migration.
The study area, Hujeong Beach, is a wave-dominated sandy shoreline located along the East Sea of South Korea. Between 2017 and 2022, twelve high-resolution topographic and bathymetric surveys were conducted using RTK drone, LiDAR, and single-beam echosounder measurements. These surveys covered coastal morphology from the beach face to approximately 50 m water depth and were strategically conducted before and after typhoons or high-energy winter wave events when significant morphological changes were expected. To supplement these discrete surveys, a total of 175 cloud-free Sentinel-2 Level-1C images from the same period were processed without atmospheric correction to preserve visible-band contrast for submerged features. CNSBs were identified using the VIS-G2R index, which enhances the spectral distinction of shallow submerged sandbars. The peak detection algorithm was applied to shore-normal brightness profiles to extract sandbar crest locations across the 0–15 m depth zone.
These satellite-derived sandbar positions used to track migration patterns and estimate morphological changes between field surveys. Analysis of the satellite-derived sandbar positions revealed consistent patterns of nearshore morphological change between field survey intervals. This study demonstrates that satellite-derived CNSB positions offer a reliable indicator of coastal morphological change, bridging the temporal gaps between field surveys and enabling cost-effective, high-frequency monitoring in wave-dominated, microtidal environments.
How to cite: Lee, B., Kim, D. H., Choi, J.-H., Chang, Y. S., Kim, C. H., and Do, J. D.: Satellite-Based Monitoring of Crescentic Nearshore Sandbar Migration at Hujeong Beach, South Korea, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-15207, https://doi.org/10.5194/egusphere-egu26-15207, 2026.
Sequence stratigraphic analysis of high-resolution seismic profiles and borehole data reveals that the late Quaternary deposits in the inner shelf off the Nakdong River in the SE Korea form a high-frequency sequence consisting of a set of lowstand, transgressive, and highstand systems tracts in response to a fifth-order (20 kyr) sea-level cycle. Four sedimentary units, each with different seismic facies, constitute the systems tracts: incised-channel fill (SU1), transgressive estuary deposits (SU2), transgressive sand layer (SU3), and a delta-shelf complex (SU4).
The lowermost unit (SU1), which overlies the sequence boundary, is interpreted as fluvial deposits formed during the last glacial period and belongs to the lowstand systems tract. The lower middle unit (SU2) lying below the ravinement surface represents a paralic component that consists of estuarine sandy mud or muddy sand developed between approximately 13 and 8 cal kyr BP, whereas the upper middle unit (SU3) above the ravinement surface corresponds to a marine component that consists of sand veneer produced by the shelf erosion during the ensuing sea-level rise (8 - 6 cal kyr BP). These two units (SU2 and SU3) belong to the transgressive systems tract. The uppermost unit (SU4) regarded as the highstand systems tract formed the Nakdong subaqueous delta including the proximal and distal systems developed after the highstand sea level at approximately 6 cal kyr BP. The lateral transition from the proximal to distal facies suggests a prograding delta system in the Nakdong River.
How to cite: Yoo, D.-G., Lee, B.-R., Hong, S.-H., Lee, G.-S., Jung, S.-K., Cho, J. H., and Choi, Y. S.: Stratigraphic Organization of the Late Quaternary Deposits in the Inner Shelf off the Nakdong River, SE Korea, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-8556, https://doi.org/10.5194/egusphere-egu26-8556, 2026.
Based on analyses of high-resolution seismic profiles and sedimentary data, we investigated the Holocene evolution and sediment budget of three shelf mud deposits distributed along the Korean Peninsula: the Southeastern Yellow Sea Mud (SEYSM), Central South Sea Mud (CSSM), and Korea Strait Shelf Mud (KSSM). These mud accumulations, which began forming around 6 ka, are integral components of the fine-grained source-to-sink system in the marginal seas of Korea. Although previous studies have examined their distribution and facies characteristics, quantitative sediment budget assessment among these deposits has remained insufficient. This study elucidates the interrelationships between the SEYSM, CSSM, and KSSM, along with the role of estuarine filtration and coastal hydrodynamics in modulating sediment transport. An estimated 32.5–43.8 × 10⁶ tons of suspended material are annually supplied to the region through multiple sediment sources. Seasonal variations in oceanic fronts and longshore currents control sediment dispersal along the Korean coast, resulting in distinct deposition patterns. The estimated annual accumulation rates are 9.0–13.2 × 10⁶ ton/year for the upper SEYSM, 5.3–8.1 × 10⁶ ton/year for the CSSM, and 4.6–6.4 × 10⁶ ton/year for the KSSM, corresponding to approximately 28–30%, 17–18%, and 14–15% of the total sediment input, respectively. Additionally, about 17–25% of fine-grained sediments are exported toward the Ulleung Basin. These sediment budget estimations provide new insights into sediment transport pathways, source-to-sink fluxes, and depositional connectivity among the Korean shelf mud systems, contributing to a refined understanding of Holocene sedimentary processes on the continental shelf.
How to cite: Lee, B.-R., Yoo, D.-G., Jung, S.-K., Cho, J. H., Lim, D. I., and Kim, G. Y.: Source-to-Sink (S2S) of the Korean Shelf Mud deposits since the 6 ka, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-2878, https://doi.org/10.5194/egusphere-egu26-2878, 2026.
