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The Eastern Mediterranean Sea is known as oil pollution hotspot because of high marine traffic and a growing number of oil and gas industrial activities inside, which makes efficient monitoring oil spills important in this area. Spaceborne Synthetic Aperture Radar (SAR) plays an important role for oil spill detection with its advantage of wide coverage and all-weather observations. However, discriminating whether the dark formations in the SAR imagery are from actual oil spills or look-alikes has been a challenging part. This study applied You Only Look Once version 4 (YOLOv4) object detection algorithm as an one-class (i.e. oil spill) object detector for learning oil spill features inside the Region of Interests (ROIs) and the background information from the rest of the image. The preliminary results pointed out that the pixel threshold for removing some tiny oil spills is suggested as they appeared regularly in the study area but are hardly visible. The average precisions (AP) of the trained model on validation and test sets are 67.80% and 65.37%, showing that the model is not overfitting on our training and validation sets. In addition, this study recommended some data augmentation strategies which might help improve the results.

Wind stress is the most important driving force for storm surge in coastal waters. Currently, the parameterization of wind stress is still not well developed and is the most uncertain parameters for storm surge models. In this paper, a storm surge model for the German Bight is developed using the model Delft3D. The data assimilation method, adjoint-free 4Dvar, which is relatively easier to be implemented than the adjoint method, is used to assimilate measured water level data into Delft3D. The storm surge prediction is more accurate when we adjusted the drag coefficient using the adjoint free data assimilation method, than in a companion forward model. The drag coefficient is consistent with results from previous studies. The wind drag coefficient is also calculated using results of a wave model. It has been found that the relation between the drag coefficient and wind speed is approximately linear in the deep water. But in the shallow water, wind drag coefficient shows larger variability due to the wave shoaling effect. The linear relation adjusted by data assimilation agrees well with that derived from a wave-related formula. It is also found that wave-related parameterization scheme is necessary for shallow waters.

In this paper, results of a tidal stream resource assessment performed for the Strait of Larantuka, Indonesia are presented. The methodology followed is comprising of the estimates of power yield and evaluation of the effects of power extraction via high-resolution, three-dimensional flow models. Power densities exceeding 10kW/m2 are observed in the main channel. Current velocities, and wake characteristics of the turbines have been resolved reasonably well with low computational cost, considering different levels of energy dissipation. Although the results are promising, investigations using in-situ measurements alongside more advanced modelling techniques are still needed, and currently underway.

Dalledonne, G. L., and Mayerle, R., 2016. Modelling of storm impacts on the Shandong peninsula coast. This paper presents results of the investigation of the effect of storms on the morphodynamics of the Yantai coastal areas in the Shandong Peninsula, China. A two-dimensional depth integrated morphodynamic model for prediction of the morphological changes during extreme events was developed and applied. The model covers the entire Bohai Sea with increasing grid resolution towards the coastal areas near Yantai. Calibration and validation using tidal constituents and measured water levels and current velocities showed that the model is capable of predicting the hydrodynamics in good agreement with observations. Emphasis was given to the proper description of the spatial distribution of the seabed sediments and bed stratigraphy. The 20 most severe storms observed in the region from 2000 to 2013 were identified and reconstructed. Storm surges with increases in mean sea level of up to 1.7 m and signif...

A multi-criteria assessment methodology that accounts for physical and environmental constraints is applied to assess the tidal stream power potential at eleven straits between Indian Ocean and inner Indonesian seas. In this paper, preliminary results of an assessment at the Strait of Larantuka are presented. The tidal stream power potential is evaluated on the basis of a calibrated and validated numerical model. It was found that the average tidal stream power density at some of the locations can exceed about 6kw/m2 and the practically exploitable energy yield from the Strait of Larantuka is about 20Gwh per year.

In this work, a two-dimensional numerical model based on Delft3D modelling system was setup to study the tidal characteristics of the Red Sea. Besides that, analyses of available observed time series of surface elevations were carried out. Sensitivity analyses of the numerical model were carried out by testing different model parameters aiming at selecting optimal settings. The model performance was evaluated against available time series of surface elevation observations. RMS error was found to vary from 0.03 to 0.1 meter, while the ADM values range from 0.02 to 0.05 meter. On the whole, the model is able to reproduce the tidal wave in the Red Sea, reflecting a consistent level of agreement with the observations and previous works. The model results suggest that the semidiurnal tidal waves play a major role in the region except in the central part of the Red Sea where amphidromic system exists. Major semidiurnal and diurnal tidal constituents were computed to generate co-charts and form factor. The results have revealed that the distribution of the co-charts of the major semidiurnal constituents M2, N2, and S2 show the existence of anticlockwise amphidromic system in the central part of the Red Sea at about 19.5°N, north of the Strait of Bab el Mandeb at 13.5°N and in the Gulf of Suez. The chart of the diurnal tidal constituent K1 showed a single counterclockwise system in the southern part of the Red Sea centred around 15.5°N. The form factor chart shows the appearance of diurnal character in the central part of the basin and the northern end of the strait. The hydrodynamics patterns under spring and neap tidal conditions were also analysed (during flood and ebb conditions). Model results showed that currents generally are weak and strongest currents are present in the strait of Bab el Mandeb and Gulf of Suez.

All North Sea countries are confronted by climate change impacts such as accelerated sea-level rise, increasing storm intensities resulting in as well higher set-up of storm surges as growing wave energy and a follow-up of morphological changes. Thus it is necessary to question the effectiveness of existing coastal protection strategies and to examine alternative strategies for coastal protection under a range of scenarios considered possible. Scenarios of accelerating sea-level rise leading to changes in sea level of up to 1 m or more by 2100 and higher set-up of storm surges with increasing wave energy have been used for planning purposes. Adaptation strategies for future coastal protection have been established in all North Sea countries with vulnerable coasts, observing two propositions: (1) structures are economic to construct in the short term and their dimensions easily adapted in the future to ensure flexibility in responding to the as yet undeterminable climate change impacts and (2) implementation of soft measures being temporarily effective and preventing counteraction to natural trends. The coastal protection strategies differ widely from country to country, not only in respect of distinct geographical boundary conditions but also in terms of the length of the planning period and the amount of regulations. Their further development is indispensable and emphasis must more and more be laid on strategies considering the effects of long-term development of coastal processes for future coastal protection. Filling gaps in knowledge is essential for developing sustainable adaptation strategies.

Mariculture (marine aquaculture) has been intensified and has created essential employment opportunities over the last two-decades in Indonesia, as well as many other countries in the world. This development has also augmented environmental concerns and questions about possible environmental impacts. Considerable amounts of nutrient waste in dissolved and particulate form were released by intensive fish faming into the environment through feed excess, soluble fish excretion and faeces production. One of the first steps to avoid the dangerous environmental impacts is careful site selection. Hence, before the implementation of fish farming mariculture activities, appropriate site conditions for culturing the species should be selected in order to minimize environmental impacts arising from the farming activities (sustainability) as well as to guarantee adequate conditions from the operational point of view (suitability). The paper focuses on the development of a Decision Support System (DSS) as a tool for the decision maker in coastal zone management and mariculture for the appropriate selection of mariculture site location. Extensive use of GIS as part of the Decision Support System was deployed in this study. The DSS is based on physical, chemical and sediment criteria as well as on data of conflicting coastal use. The GIS analysis results in a map indicating the suitable areas for the improved method of offshore cage mariculture. In this study, emphasis was placed on finfish species, however the methods and results may be employed for other species as well following some modifications. The DSS was applied for the western part of Java Sea, Indonesia. The data were acquired from direct field measurement, numerical modelling and existing information from particular agencies. Numerical modelling was used to obtain spatial and temporal distributions of hydrodynamic parameters (i.e. current velocities and water levels). The Delft3D modelling system (Delft Hydraulics, The Netherlands) was employed for this purpose. The DSS was developed under GIS application of ESRI® ArcGIS™ using weighted overlay method. Due to lack of data, some parameters were excluded from the analysis. The results showed the adequacy of the system for supporting governmental authorities in the implementation, environmental controlling, and estimation of overall carrying capacity for environmental sustainable marine fish farming.

This paper is concerned with the simultaneous measurement of terrain heights and currents using an airborne interferometric synthetic aperture radar (INSAR). For the first time, a hybrid two-antenna INSAR system with both along- and across-track baseline components is used to measure high-resolution digital elevation maps (DEMs) and current fields in a Wadden sea area. Coastal applications like the monitoring of sediment transport or the numerical modeling of morphodynamic processes require measurements of topography and currents. Classical in situ measurements of these parameters are both expensive and time consuming, or even impossible if higher spatial resolution is required. Pure along-track interferometers (ATIs) have demonstrated their ability to provide information on ocean currents, while across-track interferometric systems (XTIs) have been successfully used to measure DEMs. In this paper, a hybrid system with both ATI and XTI components is used to acquire synoptic measurement for the first time. An experiment with an airborne system taking data over a Wadden sea area is presented demonstrating the potential of the technique. A geometrical model is developed for the interferometric phase of hybrid INSAR systems. This model combines ATI and XTI techniques using a baseline that spans between two antennas consisting of along-track and across-track components. In this model, both the effect of topography and the radial velocity of the water surface enter into the resulting interferometric phase. To separate both components, the system takes data of the respective scene flying two or more tracks with different flight directions, e.g., antiparallel tracks. This approach leads to a set of linear equations that has a unique solution for the along- and cross-track phase. Finally, an additional phase bias has to be considered due to the radial velocity and the influence of squint. This is caused by a misregistration effect between both antennas, which is related to cross-track imaging of surface motion. The new INSAR technique is tested with data acquired during a campaign in February 1997 over the Weser Estuary at the German coast. The airborne INSAR system AeS-1 was used. The interferometer configuration consists of two SAR antennas separated by a mixed along-track and cross-track baseline. Two datasets acquired on antiparallel tracks are used. The calculated velocities were compared with a hydrodynamic model operated by the Federal Waterway Engineering and Research Establishment. The experimental results agree well with the numerical model. In particular, the mean velocity of 0.7 ms/sup -1/ matches in both datasets. Deviations in the fine-scale structure of the current field are discussed. Topographic analysis and validation are performed in a separate investigation. The impact of surface gravity waves and wind drift, which are known to cause significant artifacts in the ATI phase under certain circumstances, is discussed.

In this paper, an advanced methodology developed for the assessment of tidal stream resources is applied to several straits between Indian Ocean and inner Indonesian seas. Due to the high current velocities up to 3-4 m/s, the straits are particularly promising for the efficient generation of electric power. Tidal stream power potentials are evaluated on the basis of calibrated and validated high-resolution, three-dimensional numerical models. It was found that the straits under investigation have tremendous potential for the development of renewable energy production. Suitable locations for the installation of the turbines are identified in all the straits, and sites have been ranked based on the level of power density. Maximum power densities are observed in the Bali Strait, exceeding around 10kw/m2. Horizontal axis tidal turbines with a cut-in velocity of 1m/s are considered in the estimations. The highest total extractable power resulted equal to about 1,260MW in the Strait of Alas. Preliminary assessments showed that the power production at the straits under investigation is likely to exceed previous predictions reaching around 5,000MW.

A procedure, based on numerical models is proposed to investigate the processes involved during conditions of extreme water levels within the outer Elbe estuary at the German North Sea coast. Nonlinear interactions between the different processes are analyzed and adverse combinations are simulated yielding new scenarios. Various conditions in the astronomical tide, three major storm events over the North Sea, several external surges and an increase in the mean sea level are analyzed. Techniques for the modeling of each of the isolated processes are developed and individually verified. The isolated processes are temporally shifted relative to each other and superimposed in various combinations. The results obtained from the present method, provide new insights into the nonlinear interactions between the involved processes. Generally, the effects of the processes seem to be reduced in superpositions with high absolute water levels. However, due to the large scatter of the results no general relations are found. New extreme scenarios are determined by iterative maximizations of the peak water level of different superpositions around spring high tide.

In this paper the assessment of the preliminary results of a methodology to enable predictions of medium-term morphodynamics accounting for the effects of storms is carried out. The methodology integrates the approaches based on a morphological acceleration factor and on the empirical orthogonal functions to account respectively for the morphological changes on the medium and short term. In a very simplified fashion, the effects of the storms are represented by a superposition of most relevant bathymetrical changes. The effectiveness of the methodology was assessed for a coastal stretch along the German Baltic Sea. The analysis of the simulations of morphodynamics for a period of 10 years showed that the method is able to predict volumetric changes along the coastal stretches reasonably well. However it fails to describe the spatial variation of the morphological changes near the coast. Sensitivity studies show also that the results are significantly affected by the set-up scheme of the methodology. Preliminary results during the assessment of the methodology gave clues about the evolution of the morphology of the German Baltic Sea coast. The methodology can be used as a practical tool for initial assessments of tendencies of morphological evolution. Obviously, in this investigation, the method proposed to account for to the storms is a simplified representation of the reality. In this regard, further research is needed to include a more realistic representation of the chronology taking into account their intensity.

This paper investigates the predictive capability of a morphodynamic model in capturing the development of a tidal channel on the German North Sea coast which experienced migration in the last few years. A depth-averaged version of a process-based model, Delft3D, is used. A description of the set-up, calibration and validation of the process-based models is presented. Field measurements with a dense spatial and temporal coverage were used for the development of the models. Results from the hydrodynamic and sediment transport simulations were in agreement with observations. The morphodynamic model simulations were speeded up with a morphological acceleration factor in conjunction with a representative period. Results of model calibration and validation covering periods of several years proved the capability of the model to reproduce the migration of the tidal channel. According to the standards usually adopted for checking the accuracy of morphodynamic models, the performance of the model presented here was quite good. The model ability in predicting the migration in the medium-term was found to be dependent primarily on the accuracy of the starting bathymetry, characteristics of the substrata and of the mud sediment fraction as well as on the selection of the representative period. A reduction in the rate of migration of the tidal channel is predicted from 2008 till 2010.

This thesis presents a methodology of developing a quasi real time flow model in a coastal area. This model improves the water level conditions along the boundary of the flow model by the implementation of a set of neural network short term forecast.