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G.Y.H. El Serafy

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Journal article (2026) - Steven Degraer, Loreta Cornacchia, Alex Ziemba, Tundi Agardy, Sander W.K. van den Burg, Karin van de Braak, Luca A. van Duren, Annelies Declercq, Ghada El Serafy, More Authors
Nature-inclusive design (NID) of marine infrastructure comes in different forms, but always refers to the creation of optimized artificial habitat to locally enhance biodiversity. In essence, NID comprises the local addition of something non-natural to infrastructure with the aim of providing habitat for biodiversity assets in its widest sense. In its purest sense, NID is inspired by how the local environment would be without the infrastructure being present. NIDs of marine infrastructure, however, often comprise actions that promote biodiversity which does or did not naturally occur at that location. To ensure consistent use of terminology, we recommend adopting an NID trichotomy when reflecting on the appropriateness of NID applications in the marine realm, distinguishing between (i) restorative NID, linked to the restoration of lost local ecosystem values, and (ii) creative NID, referring to artificially created ecosystem assets and containing either (a) optimized infrastructure or (b) add-on structures. Restorative NID refers to measures which facilitate and speed-up nature restoration, while creative NID refers to measures to boost biodiversity ‘beyond the natural’. Beyond the importance of distinguishing different types of NID, it is important to also reflect on which biodiversity assets we elect to boost. Nowadays, much focus is placed on species richness or select species of commercial or conservational interest, while a focus on functional ecosystem assets may be more effective. A focus on functional ecosystem assets also provides better options for climate-proof NID designs. To adopt NID in an offshore renewables context, it is imperative to hold our horses and carefully consider what is the target to be achieved and how to get there. This requires a careful selection of the ecological assets that we aim to promote, while preserving the functional purpose of the marine infrastructure and incorporating the differing societal viewpoints on any potentially negative ecological consequences that may be incurred by NID solutions. In summary, restorative NID can be actively promoted, whereas creative NID requires more careful reflection; NID preferably prioritizes functional ecosystem assets and explicitly considers which ecological values to promote and why. ...

Evaluating the versatility of SARIMAX, XGBoost, and LSTM using ICOS FLUXNET and Sentinel-2 data

Journal article (2026) - Anna Spinosa, Karisma Karisma, Marieke A. Eleveld, Mario Alberto Fuentes-Monjaraz, Valeria Mobilia, Ulf Mallast, Johannes Peterseil, Ghada El Serafy
Predicting Gross Primary Productivity (GPP) is key for understanding ecosystem health and quantifying the global carbon cycle. While data-driven models have shown strong performance in capturing GPP dynamics at specific sites, their ability to generalize across ecosystems without site-specific recalibration remains largely untested. This study addresses this gap by evaluating the applicability of XGBoost and LSTM models in estimating GPP across different European ecosystems. We developed a unified (cross-site) modeling framework that integrates in-situ eddy covariance observations and Sentinel-2–derived vegetation indices using incremental learning. Models’ performance was assessed via: (i) site-specific models, developed to capture individual site characteristics, and (ii) cross-site generalization, including evaluation on an independent dataset of unseen ecosystems. SARIMAX is included as a site-specific statistical benchmark for comparison. Our findings indicate that XGBoost consistently outperformed the other models, achieving site-specific R2 values above 0.90 in forest and grassland ecosystems and an average R2 of 0.72 across unseen sites (range 0.66–0.78). LSTM exhibited better accuracy in predicting GPP peaks at site-specific level, particularly in cropland and forest ecosystems. At site-level, SARIMAX showed comparable performance to XGBoost but struggled in capturing the rapid temporal variation of GPP. These findings demonstrate the feasibility of a data-driven framework for cross-site GPP monitoring within European flux-tower networks, making a first step toward transferable GPP prediction without site-specific recalibration. ...

The Ocean Multi-use Assessment Framework (OMAF)

Journal article (2025) - A. Van Gerven, T. R.H. Kerkhove, S. Degraer, M. Lago, A. Araujo, M. Berge, A. Ziemba, G. El Serafy, J. Tamis, G. Piet, Rozemeijer M.J.C.
In the era of blue growth, ocean multi-use is gaining popularity for its potential environmental, economic and societal synergies. Expectations are high for multi-use applications to alleviate marine spatial allocation conflicts amongst users of the sea, and to stimulate innovative ways of sustainably exploiting marine resources. However, a potential barrier to implementing multi-use and co-location is the lack of a well-defined framework to evaluate the impacts of ocean multi-use projects. This paper introduces the Ocean Multi-Use Assessment Framework (OMAF), which builds upon traditional environmental impact assessments but expands to include societal and economic dimensions. In addition to these three pillars of sustainable development, the framework incorporates two critical conditions: technological feasibility and regulatory appropriateness (legal, policy, and governance). The framework promotes the use of scenarios to compare single-use and multi-use approaches in an integrated manner. This approach allows for a comprehensive, holistic evaluation of multi-use projects compared to single-use alternatives, supporting decision-making. Strong stakeholder engagement throughout the process is emphasized. The OMAF has been developed and tested under the EU-funded Horizon 2020 UNITED project, where it was applied to five multi-use pilot projects. Despite challenges related to data availability for emerging marine activities, the framework has proven applicable and effective for most projects. ...
Abstract (2024) - Felix Dols, Romain Lavaud, Brecht Stechele, Tineke Troost, Loreta Cornacchia, Luca van Duren, Lauriane Vilmin, Lorinc Meszaros, Ghada El Serafy, More Authors...
For the European Commission, the EDITO consortium is creating the European Digital Twin Ocean, a platform that integrates coastal and oceanic modelling tools with ocean observation databases and computing infrastructure. Building on EMODnet and CMEMS, EDITO Model Lab will contribute by making the next generation of ocean models more accessible. This work demonstrates one of the capabilities of the Digital Twin Ocean, focussing on human exploitation impacts on carbon fluxes. More specifically this what-if scenario is about the impact of upscaling the cultivation of shellfish in the North Sea on the carbon cycle. Upscaling the cultivation of shellfish is part of the envisioned “blue economy” and a promising option for multi-use of offshore wind parks. As shellfish are respiring organisms, they are a carbon source. At the same time shells are a carbon storage as they are built through biocalcification, a process that turns dissolved carbon and calcium into calcium carbonate. The research aims to quantify the effects of upscaling shellfish cultivation in the North Sea on the carbon cycle. This is done by implementing a biocalcification module (Stechele & Lavaud, manuscript submitted for publication in 2024), in the Dynamic Energy Budget (DEB) module integrated in Delft3D-FM’s water quality process library (Troost et al., 2010; Deltares, 2023). Our work includes assumptions about how harvesting accounts for calcium carbonate leaving the sea and is therefore sequestrated. ...
Conference paper (2024) - Anna Spinosa, Marieke Eleveld, Ulf Mallast, Johannes Peterseil, Valeria Mobilia, Karisma Karisma, Mario Alberto Fuentes-Monjaraz, Ghada El Serafy
This study addresses the challenges posed by climatic changes and biodiversity loss to ecosystem stability, by quantifying gross primary production (GPP) changes. An improved earth observation product is obtained by integrating in-situ and remote sensing data via data-driven models. Employing a user-centered strategy, our methodology builds on users' engagement, ensuring both the identification of user needs and practical product demonstrations. With GEOSS as central and integrated stakeholder, we strive for a broad interoperability and accessibility of generated outcomes. The project outcomes include a curated dataset with FAIR metadata, openly available code, and reports for reproducibility, contributing to the broader Earth Intelligence supply chain. ...
Journal article (2024) - R. Santjer, P. Mares-Nasarre, L. Vilmin, G. Y.H. El Serafy, O. Morales-Nápoles
Aquaculture at sea is gaining increasing importance, not only as a (local) food source but also due to its potential of being combined with other offshore activities such as wind parks. Nevertheless, experience of offshore aquaculture is limited. This study aims to provide a framework to evaluate offshore aquaculture suitability accounting for the probabilistic dependence between relevant variables. This framework is applied to obtain suitability maps of aquaculture for the North Sea for the blue mussel Mytilus edulis and the sugar kelp Saccharina latissima. For each of these species, three ecological variables are selected and the optimal growth and critical survival limits are defined. Here, suitability is defined as the probability of meeting these conditions. Data on the selected variables is extracted from a large-scale 3D hydrodynamic and ecological model of the northwest European Shelf, of which daily extremes are sampled. The probabilistic model is developed using bivariate copula models, which are fitted to each variable pair to describe their joint distribution function at each studied location. Empirical distribution functions are used to describe the univariate distribution function of each variable and location. Using Monte-Carlo simulations, the probability of meeting the optimal and critical limits is estimated and suitability maps accounting for the probabilistic dependence between the variables are generated. In addition, suitability maps disregarding the dependence are generated and compared to those accounting for the probabilistic dependence. It was found that considering the dependence between variables significantly improves the accuracy of the results for optimal and critical growth conditions for both species. The presented method allows to identify potential areas where blue mussel and sugar kelp cultivation is the most suitable. For instance, in this study, a north-south elongated area west of the German and Danish coast appears to be most suitable for blue mussels, while estuaries and rivers are found the most suitable for the sugar kelp. ...
Aquaculture is gaining importance in the current context of continuous growth population as a source of (local) food resources and its potential of being combined with other uses at sea (e.g.: offshore energy production or tourism). Consequently, within the European Horizon 2020 project UNITED, the combination of mussel and seaweed cultivation together with wind energy production in the German North Sea is investigated. Here, the feasibility of the mussel Mytilus edulis and seaweed Saccharina latissima based on their ecological needs is analysed. Ecological data from a three-dimensional hydrodynamic and ecological model covering the northwest European continental shelf is used. For each of the two species, three variables are selected as relevant, including in both of them the water temperature. In addition, chlorophyll-a and dissolved oxygen are considered for mussels, and dissolved inorganic nitrogen and phosphorus are selected for seaweed. Temperature is selected as dominant variable so its daily maxima for the growing months are selected together with the concomitants of the other variables. Gaussian Mixture distributions (see McLachlan and Peel (2000)) and truncated Gaussian kernel distributions (see Bowman and Azzalini (1997)) are used to model the marginal distributions of the random variables. Bivariate copulas are fitted for each pair of variables to describe their dependence structure. Finally, probabilities of being within the optimal ranges of the relevant variables are calculated. Chlorophyll-a concentration and temperature are the most limiting variables for mussels and seaweed, respectively. Relatively low probabilities are obtained, since ranges for optimal growth are considered. Generally, it is feasible to cultivate mussels and seaweed at this location based on the selected ecological variables, as the probability of variables reaching values outside growth limits for the species is low. ...
Journal article (2023) - Ghada El Serafy, Lőrinc Mészáros, Vicente Fernández, Arthur Capet, Jun She, Marcos Garcia Sotillo, Angelique Melet, Sebastien Legrand, Baptiste Mourre, More Authors...
The EuroGOOS Coastal working group examines the entire coastal value chain from coastal observations to services for coastal users. The main objective of the working group is to review the status quo, identify gaps and future steps needed to secure and improve the sustainability of the European coastal service provision. Within this framework, our white paper defines a EuroGOOS roadmap for sustained “community coastal downstream service” provision, provided by a broad EuroGOOS community with focus on the national and local scale services. After defining the coastal services in this context, we describe the main components of coastal service provision and explore community benefits and requirements through sectoral examples (aquaculture, coastal tourism, renewable energy, port, cross-sectoral) together with the main challenges and barriers to user uptake. Technology integration challenges are outlined with respect to multiparameter observations, multi-platform observations, the land-coast-ocean continuum, and multidisciplinary data integration. Finally, the technological, financial, and institutional sustainability of coastal observing and coastal service provision are discussed. The paper gives special attention to the delineation of upstream and downstream services, public-private partnerships and the important role of Copernicus in better covering the coastal zone. Therefore, our white paper is a policy and practice review providing a comprehensive overview, in-depth discussion and actionable recommendations (according to key short-term or medium-term priorities) on the envisaged elements of a roadmap for sustained coastal service provision. EuroGOOS, as an entity that unites European national operational oceanography centres, research institutes and scientists across various domains within the broader field of operational oceanography, offers to be the engine and intermediary for the knowledge transfer and communication of experiences, best practices and information, not only amongst its members, but also amongst the different (research) infrastructures, institutes and agencies that have interests in coastal oceanography in Europe. ...
Journal article (2023) - Anna Spinosa, Mario A. Fuentes-Monjaraz, Ghada El Serafy
The conservation, restoration and sustainable use of wetlands is the target of several international agreements, among which are the Sustainable Development Goals (SDGs). Earth Observation (EO) technologies can assist national authorities in monitoring activities and the environmental status of wetlands to achieve these targets. In this study, we assess the capabilities of the Sentinel-2 instrument to model Gross Primary Productivity (GPP) as a proxy for the monitoring of ecosystem health. To estimate the spatial and temporal variation of GPP, we develop an empirical model correlating in situ measurements of GPP, eight Sentinel-2 derived vegetation indexes (VIs), and different environmental drivers of GPP. The model automatically performs an interdependency analysis and selects the model with the highest accuracy and statistical significance. Additionally, the model is upscaled across larger areas and monthly maps of GPP are produced. The study methodology is applied in a marsh ecosystem located in Doñana National Park, Spain. In this application, a combination of the red-edge chlorophyll index (CLr) and rainfall data results in the highest correlation with in situ measurements of GPP and is used for the model formulation. This yields a coefficient of determination (R 2) of 0.93, Mean Absolute Error (MAE) equal to 0.52 gC m −2 day −1, Root Mean Squared Error (RMSE) equal to 0.63 gC m −2 day −1, and significance level p < 0.05. The model outputs are compared with the MODIS GPP global product (MOD17) for reference; an enhancement of the estimation of GPP is found in the applied methodology. ...
Journal article (2022) - M. Des, J.L. Gómez-Gesteira, M. de Castro, D. Iglesias, M.C. Sousa, G. ElSerafy, M. Gomez-Gesteira
Magallana gigas is a naturalized species on the north coast of Galicia (Rías Altas, Northwest Iberian Peninsula), where it was unintentionally introduced. In recent decades, a greater abundance of M. gigas has been observed on the Galician coast, expanding towards the south, reaching the Artabro Gulf (Rías Centrales, NW Galician coast), probably due to ocean warming. Although this species has been cultivated in the Rías Baixas since the early 1990s and spawning has been reported, recruitment was never observed, which is likely due to the cold water upwelled during the spawning months. The future rise in seawater temperature may favor the naturalization of the non-indigenous species M. gigas southwards, in the Rías Baixas. Thermally, the Ría de Arousa seems to be the most favorable estuary for the future settlement of M. gigas, which may occur in the next decades. The extent of thermally favorable zones within estuaries is projected to increase rapidly by mid-century, and reaching 100 % of the estuarine area by the end of the century. As has already happened in other areas of the world, the expansion and naturalization of the Pacific oyster on the Galician coast will likely affect the native communities and economic activities, making it necessary to implement monitoring and management strategies to mitigate its effect. ...
Book chapter (2022) - Ghada El Serafy, Dimitris Poursanidis, Pablo F. Méndez, Antonello Provenzale
The continual damage to ecosystem integrity, functions, and processes caused by increasing anthropogenic pressures on a global scale are threatening the supply of ecosystem services fundamental for human well-being. Marine and coastal protected areas (MCPAs) are an essential bastion of ecosystem services. Their special management and conservation status aims to ensure the maintenance of key ecosystem functions and the sustained supply of ecosystem services in the face of increasing pressures. This chapter deals with the contribution of Earth observation (EO) for the enhancement of knowledge-based conservation, management, and restoration policies in MCPAs, to ensure the sustainable provision of ecosystem services. H2020 European Project ECOPOTENTIAL has led to a novel unified framework for improving the monitoring and management of MCPAs, based on the use of EO. The framework constitutes a significant progress beyond the state of the art, due to its unique capacity to blend EO from remote sensing and field measurements. It also maximizes return on investments due to its capabilities for data mining and inclusion of versatile modeling approaches utilizing information from EO. These tools allow for assessing ecosystem service supply in current and future conditions, designing and executing needs assessment of new measurement protocols, and evaluating the requirements of new MCPAs. Open and interoperable access to data and knowledge will be ensured to researchers, managers, policy makers, and stakeholders by a GEO Ecosystem Virtual Laboratory Platform, fully integrated in GEOSS. To show how this unified framework is applied we showcase two MCPAs that include marine areas and coastal wetlands: Wadden Sea and Doñana, with specific focus on their relevance for bird conservation. ...
Coastal climate impact studies make increasing use of multi-source and multi-dimensional atmospheric and environmental datasets to investigate relationships between climate signals and the ecological response. The large quantity of numerically simulated data may, however, include redundancy, multi-colinearity and excess information not relevant to the studied processes. In such cases techniques for feature extraction and identification of latent processes prove useful. Using dimensionality reduction techniques this research provides a statistical underpinning of variable selection to study the impacts of atmospheric processes on coastal chlorophyll-a concentrations, taking the Dutch Wadden Sea as case study. Dimension reduction techniques are applied to environmental data simulated by the Delft3D coastal water quality model, the HIRLAM numerical weather prediction model and the Euro-CORDEX climate modelling experiment. The dimension reduction techniques were selected for their ability to incorporate (1) spatial correlation via multi-way methods (2), temporal correlation through Dynamic Factor Analysis, and (3) functional variability using Functional Data Analysis. The data reduction potential and explanatory value of these methods are showcased and important atmospheric variables affecting the chlorophyll-a concentration are identified. Our results indicate room for dimensionality reduction in the atmospheric variables (2 principle components can explain the majority of variance instead of 7 variables), in the chlorophyll-a time series at different locations (two characteristic patterns can describe the 10 locations), and in the climate projection scenarios of solar radiation and air temperature variables (a single principle component function explains 77% of the variation for solar radiation and 57% of the variation for air temperature). It was also found that solar radiation followed by air temperature are the most important atmospheric variables related to coastal chlorophyll-a concentration, noting that regional differences exist, for instance the importance of air temperature is greater in the Eastern Dutch Wadden Sea at Dantziggat than in the Western Dutch Wadden Sea at Marsdiep Noord. Common trends and different regional system characteristics have also been identified through dynamic factor analysis between the deeper channels and the shallower intertidal zones, where the onset of spring blooms occurs earlier. The functional analysis of climate data showed clusters of atmospheric variables with similar functional features. Moreover, functional components of Euro-CORDEX climate scenarios have been identified for radiation and temperature variables, which provide information on the dominant mode (pattern) of variation and its uncertainties. The findings suggest that radiation and temperature projections of different Euro-CORDEX scenarios share similar characteristics and mainly differ in their amplitudes and seasonal patterns, offering opportunities to construct statistical models that do not assume independence between climate scenarios but instead borrow information (“borrow strength”) from the larger pool of climate scenarios. The presented results were used in follow up studies to construct a Bayesian stochastic generator to complement existing Euro-CORDEX climate change scenarios and to quantify climate change induced trends and uncertainties in phytoplankton spring bloom dynamics in the Dutch Wadden Sea. ...
Journal article (2021) - Anna Spinosa, Alex Ziemba, Alessandra Saponieri, Leonardo Damiani, Ghada El Serafy
Remote sensing and satellite imagery have become commonplace in efforts to monitor and model various biological and physical characteristics of the Earth. The land/water interface is a continually evolving landscape of high scientific and societal interest, making the mapping and monitoring thereof particularly important. This paper aims at describing a new automated method of shoreline position detection through the utilization of Synthetic Aperture Radar (SAR) images derived from European Space Agency satellites, specifically the operational SENTINEL Series. The resultant delineated shorelines are validated against those derived from video monitoring systems and in situ monitoring; a mean distance of 1 and a maximum of 3.5 pixels is found. ...
Spring phytoplankton blooms in the southern North Sea substantially contribute to annual primary production and largely influence food web dynamics. Studying long-term changes in spring bloom dynamics is therefore crucial for understanding future climate responses and predicting implications on the marine ecosystem. This paper aims to study long term changes in spring bloom dynamics in the Dutch coastal waters, using historical coastal in-situ data and satellite observations as well as projected future solar radiation and air temperature trajectories from regional climate models as driving forces covering the twenty-first century. The main objective is to derive long-term trends and quantify climate induced uncertainties in future coastal phytoplankton phenology. The three main methodological steps to achieve this goal include (1) developing a data fusion model to interlace coastal in-situ measurements and satellite chlorophyll-a observations into a single multi-decadal signal; (2) applying a Bayesian structural time series model to produce long-term projections of chlorophyll-a concentrations over the twenty-first century; and (3) developing a feature extraction method to derive the cardinal dates (beginning, peak, end) of the spring bloom to track the historical and the projected changes in its dynamics. The data fusion model produced an enhanced chlorophyll-a time series with improved accuracy by correcting the satellite observed signal with in-situ observations. The applied structural time series model proved to have sufficient goodness-of-fit to produce long term chlorophyll-a projections, and the feature extraction method was found to be robust in detecting cardinal dates when spring blooms were present. The main research findings indicate that at the study site location the spring bloom characteristics are impacted by the changing climatic conditions. Our results suggest that toward the end of the twenty-first century spring blooms will steadily shift earlier, resulting in longer spring bloom duration. Spring bloom magnitudes are also projected to increase with a 0.4% year−1 trend. Based on the ensemble simulation the largest uncertainty lies in the timing of the spring bloom beginning and-end timing, while the peak timing has less variation. Further studies would be required to link the findings of this paper and ecosystem behavior to better understand possible consequences to the ecosystem. ...
Review (2021) - Ghada Y.H. El Serafy, Blake A. Schaeffer, Merrie-Beth Neely, Anna Spinosa, Daniel Odermatt, Kathleen C. Weathers, Theo Baracchini, Damien Bouffard, Laurence Carvalho, More authors...
Water quality measures for inland and coastal waters are available as discrete samples from professional and volunteer water quality monitoring programs and higher-frequency, near-continuous data from automated in situ sensors. Water quality parameters also are estimated from model outputs and remote sensing. The integration of these data, via data assimilation, can result in a more holistic characterization of these highly dynamic ecosystems, and consequently improve water resource management. It is becoming common to see combinations of these data applied to answer relevant scientific questions. Yet, methods for scaling water quality data across regions and beyond, to provide actionable knowledge for stakeholders, have emerged only recently, particularly with the availability of satellite data now providing global coverage at high spatial resolution. In this paper, data sources and existing data integration frameworks are reviewed to give an overview of the present status and identify the gaps in existing frameworks. We propose an integration framework to provide information to user communities through the the Group on Earth Observations (GEO) AquaWatch Initiative. This aims to develop and build the global capacity and utility of water quality data, products, and information to support equitable and inclusive access for water resource management, policy and decision making. ...
Journal article (2020) - Sara P. Cobacho, Sonja Wanke, Zoi Konstantinou, Ghada El Serafy
Ecosystem goods and services define and measure the importance of environmental resources for the well-being and prosperity of societies, considering complex social-ecological interactions and relationships. The management of coastal ecosystem services seeks to analyse the various service characteristics and potentials in relation to human activities in coastal zones which are major contributors to Blue Economies. Shellfish reefs provide many of these ecosystem services, but their efficient use and conservation depend on MSP strategies. Therefore, a conceptual framework was adapted and applied to allow an evidence-based decision making that protects and ensures a sustainable use of shellfish reefs. The Dutch Wadden Sea was selected as a case study that could benefit from the implementation of this theoretical framework. This application included an ecological modelling approach that enabled the exploration of future climate scenarios. Four shellfish-based management strategies were developed: Do nothing, Hold the line, Advance the line and Recolonization. These strategies were applied to the modelled climate scenarios and evaluated by their potential effects to the net flow of Ecosystem Services from shellfish reefs. A multi-criteria analysis identified the benefits that could be derived from actively preserving and maintaining shellfish reefs. Results indicate that the performance of different management choices varies under different scenarios, thus the selection of one or another must be well informed. Knowing the effects of different management strategies on the provision of ecosystem services creates awareness among stakeholders and can help policy makers in their decisions to efficiently manage the Dutch Wadden Sea from a conservation perspective. ...

An Application for Aquaculture Operations

Journal article (2020) - Nithin Achutha Shettigar, Biswa Bhattacharya, Lörinc Mészáros, Anna Spinosa, Ghada El Serafy
During the past decades, the aquaculture industry has developed rapidly, due to drop in wild fish catch. Water quality variables play major role in aquaculture operations, specifically seawater temperature has major impact on the metabolism of the fish species and therefore on the growth rate too. Since the fish farming business relies on the growth rate of the species to plan and operate the farm, seawater temperature becomes crucial information. With the availability of hydrodynamic modeling tools and global ocean information source such as Copernicus Marine Environment Monitoring Service (CMEMS), seawater temperature can be simulated for practically any coast with dynamic downscaling approach. However, the simulated data needs to be assessed for uncertainties for enabling informed decision making using such model predictions. In this paper, a coastal 3D hydrodynamic model aiming at simulating seawater temperature is developed for the southern Aegean Sea, Greece using the Delft3D Flexible Mesh modeling tool. Seawater temperature is impacted by atmospheric forces; therefore, uncertainties are assessed for seawater temperature using ensemble atmospheric forcing functions of the European Centre for Medium-Range Weather Forecasts (ECMWF) ERA5. Spatial analysis of the uncertainty indicates regions of different seawater temperature behavior within the model domain. Seasonal behavior of the vertical temperature gradient suggests that farms need to adapt different operational strategies in different seasons to make best use of the seawater temperature. The application of CMEMS data along with ECMWF ERA5 ensemble atmospheric forcing members proves to be beneficial in analyzing the uncertainties both in spatial and vertical gradient of seawater temperature. ...

Supporting uncertainty quantification in marine and coastal ecosystems

Available climate change projections, which can be used for quantifying future changes in marine and coastal ecosystems, usually consist of a few scenarios. Studies addressing ecological impacts of climate change often make use of a low- (RCP2.6), moderate- (RCP4.5) or high climate scenario (RCP8.5), without taking into account further uncertainties in these scenarios. In this research a methodology is proposed to generate further synthetic scenarios, based on existing datasets, for a better representation of climate change induced uncertainties. The methodology builds on Regional Climate Model scenarios provided by the EURO-CORDEX experiment. In order to generate new realizations of climate variables, such as radiation or temperature, a hierarchical Bayesian model is developed. In addition, a parameterized time series model is introduced, which includes a linear trend component, a seasonal shape with varying amplitude and time shift, and an additive residual term. The seasonal shape is derived with the non-parametric locally weighted scatterplot smoothing, and the residual term includes the smoothed variance of residuals and independent and identically distributed noise. The distributions of the time series model parameters are estimated through Bayesian parameter inference with Markov chain Monte Carlo sampling (Gibbs sampler). By sampling from the predictive distribution numerous new statistically representative synthetic scenarios can be generated including uncertainty estimates. As a demonstration case, utilizing these generated synthetic scenarios and a physically based ecological model (Delft3D-WAQ) that relates climate variables to ecosystem variables, a probabilistic simulation is conducted to further propagate the climate change induced uncertainties to marine and coastal ecosystem indicators. ...
Journal article (2019) - Solveig Höfer, Alex Ziemba, Ghada El Serafy
The concept of ecosystem services is gaining attention in the context of sustainable resource management. However, it is inherently difficult to account for tangible and intangible services in a combined model. The aim of this study is to extend the definition of ecosystem service trade-offs by using Bayesian Networks to capture the relationship between tangible and intangible ecosystem services. Tested is the potential of creating such a network based on existing literature and enhancement via expert elicitation. This study discusses the significance of expert elicitation to enhance the value of a Bayesian Network in data-restricted case studies, underlines the importance of inclusion of experts’ certainty, and demonstrates how multiple sources of knowledge can be combined into one model accounting for both tangible and intangible ecosystem services. Bayesian Networks appear to be a promising tool in this context, nevertheless, this approach is still in need of further refinement in structure and applicable guidelines for expert involvement and elicitation for a more unified methodology. ...
Journal article (2018) - Matei Ţene, Dana E. Stuparu, Dorota Kurowicka, Ghada Y. El Serafy
This paper describes a novel sensitivity analysis method, able to handle dependency relationships between model parameters. The starting point is the popular Morris (1991) algorithm, which was initially devised under the assumption of parameter independence. This important limitation is tackled by allowing the user to incorporate dependency information through a copula. The set of model runs obtained using latin hypercube sampling, are then used for deriving appropriate sensitivity measures. Delft3D-WAQ (Deltares, 2010) is a sediment transport model with strong correlations between input parameters. Despite this, the parameter ranking obtained with the newly proposed method is in accordance with the knowledge obtained from expert judgment. However, under the same conditions, the classic Morris method elicits its results from model runs which break the assumptions of the underlying physical processes. This leads to the conclusion that the proposed extension is superior to the classic Morris algorithm and can accommodate a wide range of use cases. ...