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J. Mar. Sci. Eng., Volume 4, Issue 4 (December 2016) – 23 articles

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1802 KiB  
Article
Variations in the Wave Climate and Sediment Transport Due to Climate Change along the Coast of Vietnam
by Ali Dastgheib, Johan Reyns, Supot Thammasittirong, Sutat Weesakul, Marcus Thatcher and Roshanka Ranasinghe
J. Mar. Sci. Eng. 2016, 4(4), 86; https://doi.org/10.3390/jmse4040086 - 15 Dec 2016
Cited by 20 | Viewed by 4884
Abstract
This study quantifies the climate change (CC)-driven variations in wave characteristics and the resulting variations in potential longshore sediment transport rate along the ~2000 km mainland coast of Vietnam. Wind fields derived from global circulation models (GCM) for current and future (2041–2060 and [...] Read more.
This study quantifies the climate change (CC)-driven variations in wave characteristics and the resulting variations in potential longshore sediment transport rate along the ~2000 km mainland coast of Vietnam. Wind fields derived from global circulation models (GCM) for current and future (2041–2060 and 2081–2100) climate conditions are used to force a numerical wave model (MIKE21 SW) to derive the deep water wave climate. The offshore wave climate is translated to nearshore wave conditions using another numerical model (Simulating WAves Nearshore—SWAN) and finally, a sediment transport model (GENEralized model for Simulating Shoreline Change—GENESIS) is used to estimate potential sediment transport for current and future climate conditions. Results indicate that CC effects are substantially different in the northern, central and southern parts of the coast of Vietnam. The 2081–2100 mean significant wave height along the northern coast is estimated to be up to 8 cm lower (relative to 1981–2000), while projections for central and southern coasts of Vietnam indicate slightly higher (increases of up to 5 cm and 7 cm respectively). Wave direction along the northern coast of Vietnam is projected to shift by up to 4° towards the south (clockwise) by 2081–2100 (relative to 1981–2000), up to 6° clockwise along the central coast and by up to 8° anti-clockwise (to the north) along the southern coast. The projected potential longshore sediment transport rates show very substantial and spatially variable future changes in net transport rates along the coast of Vietnam, with increases of up to 0.5 million m3/year at some locations (by 2081–2100 relative to 1981–2000), implying major changes in future coastline position and/or orientation. The vicinity of the highly developed city of Da Nang is likely to be particularly subject to coastline changes, with potentially an additional 875,000 m3 of sand being transported away from the area per year by the turn of the 21st century. Full article
(This article belongs to the Special Issue Modelling Waves in Coasts and Estuaries)
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8639 KiB  
Article
Effect of Coastal Erosion on Storm Surge: A Case Study in the Southern Coast of Rhode Island
by Alex Shaw, Mohammad Reza Hashemi, Malcolm Spaulding, Bryan Oakley and Chris Baxter
J. Mar. Sci. Eng. 2016, 4(4), 85; https://doi.org/10.3390/jmse4040085 - 07 Dec 2016
Cited by 6 | Viewed by 6222
Abstract
The objective of this study was to assess the effect of shoreline retreat and dune erosion on coastal flooding in a case study located in the southern coast of Rhode Island, USA. Using an extensive dataset collected during 2011, an ADCIRC model was [...] Read more.
The objective of this study was to assess the effect of shoreline retreat and dune erosion on coastal flooding in a case study located in the southern coast of Rhode Island, USA. Using an extensive dataset collected during 2011, an ADCIRC model was developed to simulate the propagation of storm surge in the coastal areas, including coastal inlets and ponds. A simplified methodology, based on the geological assessment of historical trends of the shoreline retreat and dune erosion in this area, was incorporated in the model to represent coastal erosion. The results showed that for extreme storms (e.g., a 100-year event), where coastal dunes are overtopped and low-lying areas are flooded, the flooding extent is not significantly sensitive to coastal erosion. However, failure of the dunes leads to a significant increase of the flooding extent for smaller storms. Substantial dampening of the storm surge elevation in coastal ponds for moderate and small storms was associated with coastal inlets connecting to coastal ponds which are often not resolved in regional surge models. The shoreline change did not significantly affect the extent of flooding. It was also shown that the accuracy of a storm surge model highly depends on its ability to resolve coastal inlets, which is critical for reliable storm surge predictions in areas with inlet-basin systems. Full article
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1935 KiB  
Article
Enhancement of Protein and Pigment Content in Two Chlorella Species Cultivated on Industrial Process Water
by Hamed Safafar, Patrick Uldall Nørregaard, Anita Ljubic, Per Møller, Susan Løvstad Holdt and Charlotte Jacobsen
J. Mar. Sci. Eng. 2016, 4(4), 84; https://doi.org/10.3390/jmse4040084 - 02 Dec 2016
Cited by 77 | Viewed by 7346
Abstract
Chlorella pyrenoidosa and Chlorella vulgaris were cultivated in pre-gasified industrial process water with high concentration of ammonia representing effluent from a local biogas plant. The study aimed to investigate the effects of growth media and cultivation duration on the nutritional composition of biomass. [...] Read more.
Chlorella pyrenoidosa and Chlorella vulgaris were cultivated in pre-gasified industrial process water with high concentration of ammonia representing effluent from a local biogas plant. The study aimed to investigate the effects of growth media and cultivation duration on the nutritional composition of biomass. Variations in proteins, lipid, fatty acid composition, amino acids, tocopherols, and pigments were studied. Both species grew well in industrial process water. The contents of proteins were affected significantly by the growth media and cultivation duration. Microalga Chlorella pyrenoidosa produced the highest concentrations of protein (65.2% ± 1.30% DW) while Chlorella vulgaris accumulated extremely high concentrations of lutein and chlorophylls (7.14 ± 0.66 mg/g DW and 32.4 ± 1.77 mg/g DW, respectively). Cultivation of Chlorella species in industrial process water is an environmentally friendly, sustainable bioremediation method with added value biomass production and resource valorization, since the resulting biomass also presented a good source of proteins, amino acids, and carotenoids for potential use in aquaculture feed industry. Full article
(This article belongs to the Special Issue Emerging Biomolecular Technologies in Marine Science)
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4671 KiB  
Article
Line Force and Damping at Full and Partial Stator Overlap in a Linear Generator for Wave Power
by Liselotte Ulvgård, Linnea Sjökvist, Malin Göteman and Mats Leijon
J. Mar. Sci. Eng. 2016, 4(4), 81; https://doi.org/10.3390/jmse4040081 - 28 Nov 2016
Cited by 17 | Viewed by 4989
Abstract
A full scale linear generator for wave power has been experimentally evaluated by measuring the line force and translator position throughout the full translator stroke. The measured line force, in relation to translator speed, generator damping and stator overlap, has been studied by [...] Read more.
A full scale linear generator for wave power has been experimentally evaluated by measuring the line force and translator position throughout the full translator stroke. The measured line force, in relation to translator speed, generator damping and stator overlap, has been studied by comparing the line force and the damping coefficient, γ , for multiple load cases along the translator stroke length. The study also compares the generator’s behavior during upward and downward motion, studies oscillations and determines the no load losses at two different speeds. The generator damping factor, γ , was determined for five different load cases during both upward and downward motion. The γ value was found to be constant for full stator overlap and to decrease linearly with a decreasing overlap, as the translator moved towards the endstops. The decline varied with the external load case, as previously suggested but not shown. In addition, during partial stator overlap, a higher γ value was noted as the translator was leaving the stator, compared to when it was entering the stator. Finally, new insights were gained regarding how translator weight and generator damping will affect the translator downward motion during offshore operation. This is important for power production and for avoiding damaging forces acting on the wave energy converter during operation. Full article
(This article belongs to the Special Issue Ocean Wave Energy Conversion)
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Article
Procedure for Application-Oriented Optimisation of Marine Propellers
by Florian Vesting, Rickard E. Bensow, Rikard Johansson, Robert Gustafsson and Nicole Costa
J. Mar. Sci. Eng. 2016, 4(4), 83; https://doi.org/10.3390/jmse4040083 - 26 Nov 2016
Cited by 3 | Viewed by 6433
Abstract
The use of automated optimisation in engineering applications is emerging. In particular, nature inspired algorithms are frequently used because of their variability and robust application in constraints and multi-objective optimisation problems. The purpose of this paper is the comparison of four different algorithms [...] Read more.
The use of automated optimisation in engineering applications is emerging. In particular, nature inspired algorithms are frequently used because of their variability and robust application in constraints and multi-objective optimisation problems. The purpose of this paper is the comparison of four different algorithms and several optimisation strategies on a set of seven test propellers in realistic industrial design setting. The propellers are picked from real commercial projects and the manual final designs were delivered to customers. The different approaches are evaluated and final results of the automated optimisation toolbox are compared with designs generated in a manual design process. We identify a two-stage optimisation for marine propellers, where the geometry is first modified by parametrised geometry distribution curves to gather knowledge of the test case. Here we vary the optimisation strategy in terms of applied algorithms, constraints and objectives. A second supporting optimisation aims to improve the design by locally changing the geometry, based on the results of the first optimisation. The optimisation algorithms and strategies yield propeller designs that are comparable to the manually designed propeller blade geometries, thus being suitable as robust and advanced design support tools. The supporting optimisation, with local modification of the blade geometry and the proposed cavity shape constraints, features particular good performance in modifying cavitation on the blade and is, with the AS NSGA-II (adaptive surrogate-assisted NSGA-II), superior in lead time. Full article
(This article belongs to the Special Issue Marine Propellers and Propulsion)
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8335 KiB  
Article
Development of the Hydrodynamic Model for Long-Term Simulation of Water Quality Processes of the Tidal James River, Virginia
by Jian Shen, Ya Wang and Mac Sisson
J. Mar. Sci. Eng. 2016, 4(4), 82; https://doi.org/10.3390/jmse4040082 - 24 Nov 2016
Cited by 12 | Viewed by 5387
Abstract
Harmful algal blooms (HABs) have frequently occurred in the James River. The State has convened a Scientific Advisory Panel (SAP) to review the James River chlorophyll-a standards. The SAP will conduct a scientific study to review the basis for setting the chlorophyll-a standards. [...] Read more.
Harmful algal blooms (HABs) have frequently occurred in the James River. The State has convened a Scientific Advisory Panel (SAP) to review the James River chlorophyll-a standards. The SAP will conduct a scientific study to review the basis for setting the chlorophyll-a standards. To support the SAP study of chlorophyll-a standards, the State of Virginia has decided to develop a numerical modeling system that is capable of simulating phytoplankton and HABs. The modeling system includes a watershed model, a three-dimensional hydrodynamic model and water quality models. The focus of this study will be on the development and verification of the hydrodynamic model. In order to simulate the complex geometry of the James River, a high-resolution model has been implemented. The model has been calibrated for a long-term period of 23 years. A series of model experiments was conducted to evaluate the impact of forcings on dynamic simulation and transport time. It was found that freshwater discharge is the most sensitive for an accurate simulation of salinity and transport time. The water age predicted by the model in the tidal freshwater region represents the fluctuation of transport processes, and it has a good correlation with the algal bloom, while at the downstream, the transport time simulation agrees with the delay of the HAB in the mesohaline of the James after the HAB occurred in the Elizabeth River due to the transport processes. The results indicate that the hydrodynamic model is capable of simulating the dynamic processes of the James and driving water quality models in the James River. Full article
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4357 KiB  
Article
Modeling Water Clarity and Light Quality in Oceans
by Mohamed A. Abdelrhman
J. Mar. Sci. Eng. 2016, 4(4), 80; https://doi.org/10.3390/jmse4040080 - 24 Nov 2016
Cited by 14 | Viewed by 5683
Abstract
Phytoplankton is a primary producer of organic compounds, and it forms the base of the food chain in ocean waters. The concentration of phytoplankton in the water column controls water clarity and the amount and quality of light that penetrates through it. The [...] Read more.
Phytoplankton is a primary producer of organic compounds, and it forms the base of the food chain in ocean waters. The concentration of phytoplankton in the water column controls water clarity and the amount and quality of light that penetrates through it. The availability of adequate light intensity is a major factor in the health of algae and phytoplankton. There is a strong negative coupling between light intensity and phytoplankton concentration (e.g., through self-shading by the cells), which reduces available light and in return affects the growth rate of the cells. Proper modeling of this coupling is essential to understand primary productivity in the oceans. This paper provides the methodology to model light intensity in the water column, which can be included in relevant water quality models. The methodology implements relationships from bio-optical models, which use phytoplankton chlorophyll a (chl-a) concentration as a surrogate for light attenuation, including absorption and scattering by other attenuators. The presented mathematical methodology estimates the reduction in light intensity due to absorption by pure seawater, chl-a pigment, non-algae particles (NAPs) and colored dissolved organic matter (CDOM), as well as backscattering by pure seawater, phytoplankton particles and NAPs. The methods presented facilitate the prediction of the effects of various environmental and management scenarios (e.g., global warming, altered precipitation patterns, greenhouse gases) on the wellbeing of phytoplankton communities in the oceans as temperature-driven chl-a changes take place. Full article
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14951 KiB  
Article
Tidal Datum Changes Induced by Morphological Changes of North Carolina Coastal Inlets
by Jindong Wang and Edward Myers
J. Mar. Sci. Eng. 2016, 4(4), 79; https://doi.org/10.3390/jmse4040079 - 18 Nov 2016
Cited by 3 | Viewed by 4189
Abstract
In support of the National Oceanic and Atmospheric Administration’s VDatum program, a new version of a tidal datum product for the North Carolina coastal waters has been developed to replace the initial version released in 2004. Compared with the initial version, the new [...] Read more.
In support of the National Oceanic and Atmospheric Administration’s VDatum program, a new version of a tidal datum product for the North Carolina coastal waters has been developed to replace the initial version released in 2004. Compared with the initial version, the new version used a higher resolution grid to cover more areas and incorporated up-to-date tide, bathymetry, and shoreline data. Particularly, the old bathymetry datasets that were collected from the 1930s to the 1970s and were used in the initial version have been replaced by the new bathymetry datasets collected in the 2010s in the new version around five North Carolina inlets. This study aims at evaluating and quantifying tidal datum changes induced by morphological changes over about 40 to 80 years around the inlets. A series of tidal simulations with either the old or new bathymetry datasets used around five inlets were conducted to quantify the consequent tidal datum changes. The results showed that around certain inlets, approximately 10% change in the averaged depth could result in over 30% change in the tidal datum magnitude. Further investigation also revealed that tidal datum changes behind the barrier islands are closely associated with the cross-inlet tidal flux changes. Full article
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5523 KiB  
Article
Climate Change Impacts on Future Wave Climate around the UK
by William G. Bennett, Harshinie Karunarathna, Nobuhito Mori and Dominic E. Reeve
J. Mar. Sci. Eng. 2016, 4(4), 78; https://doi.org/10.3390/jmse4040078 - 18 Nov 2016
Cited by 15 | Viewed by 5796
Abstract
Understanding the changes in future storm wave climate is crucial for coastal managers and planners to make informed decisions required for sustainable coastal management and for the renewable energy industry. To investigate potential future changes to storm climate around the UK, global wave [...] Read more.
Understanding the changes in future storm wave climate is crucial for coastal managers and planners to make informed decisions required for sustainable coastal management and for the renewable energy industry. To investigate potential future changes to storm climate around the UK, global wave model outputs of two time slice experiments were analysed with 1979–2009 representing present conditions and 2075–2100 representing the future climate. Three WaveNet buoy sites around the United Kingdom, which represent diverse site conditions and have long datasets, were chosen for this study. A storm event definition (Dissanayake et al., 2015) was used to separate meteorologically-independent storm events from wave data, which in turn allowed storm wave characteristics to be analysed. Model outputs were validated through a comparison of the modelled storm data with observed storm data for overlapping periods. Although no consistent trends across all future clusters were observed, there were no significant increases in storm wave height, storm count or storm power in the future, at least according to the global wave projection results provided by the chosen model. Full article
(This article belongs to the Special Issue Modelling Waves in Coasts and Estuaries)
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7142 KiB  
Article
Model Development and Hindcast Simulations of NOAA’s Gulf of Maine Operational Forecast System
by Zizang Yang, Philip Richardson, Yi Chen, John G. W. Kelley, Edward Myers, Frank Aikman III, Machuan Peng and Aijun Zhang
J. Mar. Sci. Eng. 2016, 4(4), 77; https://doi.org/10.3390/jmse4040077 - 17 Nov 2016
Cited by 6 | Viewed by 4733
Abstract
The National Ocean Service (NOS) of National Oceanic and Atmospheric Administration is developing an operational nowcast/forecast system for the Gulf of Maine (GoMOFS). The system aims to produce real-time nowcasts and short-range forecast guidance for water levels, 3-dimensional currents, water temperature, and salinity [...] Read more.
The National Ocean Service (NOS) of National Oceanic and Atmospheric Administration is developing an operational nowcast/forecast system for the Gulf of Maine (GoMOFS). The system aims to produce real-time nowcasts and short-range forecast guidance for water levels, 3-dimensional currents, water temperature, and salinity over the broad GoM region. GoMOFS will be implemented using the Regional Ocean Model System (ROMS). This paper describes the system setup and results from a one-year (2012) hindcast simulation. The hindcast performance was evaluated using the NOS standard skill assessment software. The results indicate favorable agreement between observations and model forecasts. The root-mean-squared errors are about 0.12 m for water level, less than 1.5 °C for temperature, less than 1.5 psu for salinity, and less than 0.2 m/s for currents. It is anticipated to complete the system development and the transition into operations in fiscal year 2017. Full article
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6707 KiB  
Article
Simulating the Response of Estuarine Salinity to Natural and Anthropogenic Controls
by Vladimir A. Paramygin, Y. Peter Sheng, Justin R. Davis and Karen Herrington
J. Mar. Sci. Eng. 2016, 4(4), 76; https://doi.org/10.3390/jmse4040076 - 16 Nov 2016
Cited by 2 | Viewed by 4077
Abstract
The response of salinity in Apalachicola Bay, Florida to changes in water management alternatives and storm and sea level rise is studied using an integrated high-resolution hydrodynamic modeling system based on Curvilinear-grid Hydrodynamics in 3D (CH3D), an oyster population model, and probability analysis. [...] Read more.
The response of salinity in Apalachicola Bay, Florida to changes in water management alternatives and storm and sea level rise is studied using an integrated high-resolution hydrodynamic modeling system based on Curvilinear-grid Hydrodynamics in 3D (CH3D), an oyster population model, and probability analysis. The model uses input from river inflow, ocean and atmospheric forcing and is verified with long-term water level and salinity data, including data from the 2004 hurricane season when four hurricanes impacted the system. Strong freshwater flow from the Apalachicola River and good connectivity of the bay to the ocean allow the estuary to restore normal salinity conditions within a few days after the passage of a hurricane. Various scenarios are analyzed; some based on observed data and others using altered freshwater inflow. For observed flow, simulated salinity agrees well with the observed values. In scenarios that reflect increased water demand (~1%) upstream of the Apalachicola River, the model results show slightly (less than 5%) increased salinity inside the Bay. A worst-case sea-level rise (~1 m by 2100) could increase the bay salinity by up to 20%. A hypothesis that a Sumatra gauge may not fully represent the flow into Apalachicola Bay was tested and appears to be substantiated. Full article
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8714 KiB  
Article
Biofouling on Coated Carbon Steel in Cooling Water Cycles Using Brackish Seawater
by Pauliina Rajala, Elina Sohlberg, Outi Priha, Irina Tsitko, Henri Väisänen, Mikko Tausa and Leena Carpén
J. Mar. Sci. Eng. 2016, 4(4), 74; https://doi.org/10.3390/jmse4040074 - 11 Nov 2016
Cited by 9 | Viewed by 5979
Abstract
Water cooling utilizing natural waters is typically used for cooling large industrial facilities such as power plants. The cooling water cycles are susceptible to biofouling and scaling, which may reduce heat transfer capacity and enhance corrosion. The performance of two fouling-release coatings combined [...] Read more.
Water cooling utilizing natural waters is typically used for cooling large industrial facilities such as power plants. The cooling water cycles are susceptible to biofouling and scaling, which may reduce heat transfer capacity and enhance corrosion. The performance of two fouling-release coatings combined with hypochlorite treatment were studied in a power plant utilizing brackish sea water from the Baltic Sea for cooling. The effect of hypochlorite as an antifouling biocide on material performance and species composition of microfouling formed on coated surfaces was studied during the summer and autumn. Microfouling on surfaces of the studied fouling-release coatings was intensive in the cooling water cycle during the warm summer months. As in most cases in a natural water environment the fouling consisted of both inorganic fouling and biofouling. Chlorination decreased the bacterial number on the surfaces by 10–1000 fold, but the efficacy depended on the coating. In addition to decreasing the bacterial number, the chlorination also changed the microbial species composition, forming the biofilm on the surfaces of two fouling-release coatings. TeknoTar coating was proven to be more efficient in combination with the hypochlorite treatment against microfouling under these experimental conditions. Full article
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1979 KiB  
Review
To What Extent Can Existing Research Help Project Climate Change Impacts on Biodiversity in Aquatic Environments? A Review of Methodological Approaches
by Anders Forsman, Hanna Berggren, Mats Åström and Per Larsson
J. Mar. Sci. Eng. 2016, 4(4), 75; https://doi.org/10.3390/jmse4040075 - 10 Nov 2016
Cited by 10 | Viewed by 6076
Abstract
It is broadly accepted that continued global warming will pose a major threat to biodiversity in the 21st century. But how reliable are current projections regarding consequences of future climate change for biodiversity? To address this issue, we review the methodological approaches in [...] Read more.
It is broadly accepted that continued global warming will pose a major threat to biodiversity in the 21st century. But how reliable are current projections regarding consequences of future climate change for biodiversity? To address this issue, we review the methodological approaches in published studies of how life in marine and freshwater environments responds to temperature shifts. We analyze and compare observational field surveys and experiments performed either in the laboratory or under natural conditions in the wild, the type of response variables considered, the number of species investigated, study duration, and the nature and magnitude of experimental temperature manipulations. The observed patterns indicate that, due to limitations of study design, ecological and evolutionary responses of individuals, populations, species, and ecosystems to temperature change were in many cases difficult to establish, and causal mechanism(s) often remained ambiguous. We also discovered that the thermal challenge in experimental studies was 10,000 times more severe than reconstructed estimates of past and projections of future warming of the oceans, and that temperature manipulations also tended to increase in magnitude in more recent studies. These findings raise some concerns regarding the extent to which existing research can increase our understanding of how higher temperatures associated with climate change will affect life in aquatic environments. In view of our review findings, we discuss the trade-off between realism and methodological tractability. We also propose a series of suggestions and directions towards developing a scientific agenda for improving the validity and inference space of future research efforts. Full article
(This article belongs to the Special Issue Impacts of Climate Change on a Marginal Ecosystems—the Baltic Sea)
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Article
Application of the Forward Sensitivity Method to a GWCE-Based Shallow Water Model
by Evan M. Tromble, Sivaramakrishnan Lakshmivarahan, Randall L. Kolar and Kendra M. Dresback
J. Mar. Sci. Eng. 2016, 4(4), 73; https://doi.org/10.3390/jmse4040073 - 10 Nov 2016
Cited by 1 | Viewed by 3496
Abstract
The Forward Sensitivity Method (FSM) is applied to a GWCE-based shallow water model to analyze the sensitivity to the numerical parameter, G, that determines the balance between the wave and primitive forms of the continuity equation. Results show that the sensitivity to [...] Read more.
The Forward Sensitivity Method (FSM) is applied to a GWCE-based shallow water model to analyze the sensitivity to the numerical parameter, G, that determines the balance between the wave and primitive forms of the continuity equation. Results show that the sensitivity to G calculated in the sensitivity evolution portion of the FSM is consistent with the actual sensitivity to G computed from multiple simulations using finite differences. The data assimilation step in the FSM is shown to be effective in selecting G that minimizes an objective function, in this case model errors based on sensitivities. Additionally, the FSM sensitivity results show 2 Δ x oscillations in the elevation and velocity fields develop when G is increased too high, suggesting the FSM may be an effective tool for determining the upper limit of G for real-world applications. Full article
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Article
Improvements for the Western North Atlantic, Caribbean and Gulf of Mexico ADCIRC Tidal Database (EC2015)
by Christine Szpilka, Kendra Dresback, Randall Kolar, Jesse Feyen and Jindong Wang
J. Mar. Sci. Eng. 2016, 4(4), 72; https://doi.org/10.3390/jmse4040072 - 08 Nov 2016
Cited by 22 | Viewed by 6575
Abstract
This research details the development and validation of an updated constituent tidal database for the Western North Atlantic, Caribbean and Gulf of Mexico (WNAT) region, referred to as the EC2015 database. Regional databases, such as EC2015, provide much higher resolution than global databases [...] Read more.
This research details the development and validation of an updated constituent tidal database for the Western North Atlantic, Caribbean and Gulf of Mexico (WNAT) region, referred to as the EC2015 database. Regional databases, such as EC2015, provide much higher resolution than global databases allowing users to more accurately define the tidal forcing on smaller sub-region domains. The database last underwent major updates in 2001 and was developed using the two-dimensional, depth-integrated form of the coastal hydrodynamic model, ADvanced CIRCulation (ADCIRC), which solves the shallow-water equations in the generalized wave continuity equation form. Six main areas of improvement are examined: (1) placement of the open ocean boundary; (2) higher coastal resolution using Vertical Datum (VDatum) models; (3) updated bathymetry from global databases; (4) updated boundary forcing compared using two global tidal databases; (5) updated bottom friction formulations; and (6) improved model physics by incorporating the advective terms in ADCIRC. The skill of the improved database is compared to that of its predecessor and is calculated using harmonic data from the National Oceanic and Atmospheric Administration Center for Operational Oceanographic Products and Services (NOAA CO-OPS) stations and historic International Hydrographic Organization (IHO) data. Overall, the EC2015 database significantly reduces errors realized in the EC2001 database and improves the quality of coastal tidal constituents available for smaller sub-regional models in the Western North Atlantic, Caribbean and Gulf of Mexico (WNAT) region. Full article
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Article
Propeller Cavitation in Non-Uniform Flow and Correlation with the Near Pressure Field
by Francisco Alves Pereira, Fabio Di Felice and Francesco Salvatore
J. Mar. Sci. Eng. 2016, 4(4), 70; https://doi.org/10.3390/jmse4040070 - 05 Nov 2016
Cited by 41 | Viewed by 6358
Abstract
An experimental study is carried out in a cavitation tunnel on a propeller operating downstream of a non-uniform wake. The goal of this work is to establish quantitative correlations between the near pressure field and the cavitation pattern that takes place on the [...] Read more.
An experimental study is carried out in a cavitation tunnel on a propeller operating downstream of a non-uniform wake. The goal of this work is to establish quantitative correlations between the near pressure field and the cavitation pattern that takes place on the propeller blades. The pressure field is measured at the walls of the test section and in the near wake of the propeller and is combined with quantitative high-speed image recording of the cavitation pattern. Through harmonic analysis of the pressure data and image processing techniques that allow retrieving the cavitation extension and volume, we discuss the potential sources that generate the pressure fluctuations. Time correlations are unambiguously established between pressure peak fluctuations and cavitation collapse events, based on the Rayleigh collapse time. Finally, we design a model to predict the cavitation-induced pressure fluctuations from the derivation of the cavitation volume acceleration. A remarkable agreement is observed with the actual pressure field. Full article
(This article belongs to the Special Issue Marine Propellers and Propulsion)
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Article
Controls on Nitrous Oxide Production in, and Fluxes from a Coastal Aquifer in Long Island, NY, USA
by Caitlin Young, Jonathan B. Martin and Gilbert N. Hanson
J. Mar. Sci. Eng. 2016, 4(4), 71; https://doi.org/10.3390/jmse4040071 - 04 Nov 2016
Cited by 3 | Viewed by 3894
Abstract
Nitrous oxide (N2O) has 265 times greater greenhouse potential than carbon dioxide and its atmospheric concentration has increased by about 20% since industrialization; however, N2O production and emissions from aquatic systems are poorly constrained. To evaluate N2O [...] Read more.
Nitrous oxide (N2O) has 265 times greater greenhouse potential than carbon dioxide and its atmospheric concentration has increased by about 20% since industrialization; however, N2O production and emissions from aquatic systems are poorly constrained. To evaluate N2O fluxes associated with meteoric groundwater discharge to coastal zones, we measured N2O concentrations in May and October 2011 from two discharge points of the Upper Glacial aquifer on Long Island, NY, USA. One coastal zone contains only fresh water and the other contains an upper saline zone. N2O concentrations decreased by around 40% for the fresh water and a factor of two for the salt water from May to October, 2011. Fluxes were around 100 to 200 times greater from the freshwater (246 to 448 µmol/m shoreline/day) than saltwater aquifer (26.1 to 26.5 µmol/m shoreline/day). N2O concentrations correlate positively with NO3 and dissolved oxygen concentrations and negatively with salinity, dissolved organic carbon (DOC) and N2 denitrification concentrations. The smaller saltwater N2O export resulted from DOC enrichment in the upper saline zone, which appears to have driven denitrification to completion, removed N2O, and increased N2 denitrification. DOC concentrations should be considered in global N2O flux estimates for coastal aquifers. Full article
(This article belongs to the Special Issue Coastal Groundwater Dynamics and Its Derived Chemical Fluxes)
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Article
Combining Inverse and Transport Modeling to Estimate Bacterial Loading and Transport in a Tidal Embayment
by Mac Sisson, Jian Shen and Anne Schlegel
J. Mar. Sci. Eng. 2016, 4(4), 69; https://doi.org/10.3390/jmse4040069 - 02 Nov 2016
Viewed by 4166
Abstract
Poquoson River is a tidal coastal embayment located along the Western Shore of the Chesapeake Bay about 4 km south of the York River mouth in the City of Poquoson and in York County, Virginia. Its drainage area has diversified land uses, including [...] Read more.
Poquoson River is a tidal coastal embayment located along the Western Shore of the Chesapeake Bay about 4 km south of the York River mouth in the City of Poquoson and in York County, Virginia. Its drainage area has diversified land uses, including high densities of residence, agricultural, salt marsh land uses, as well as a National Wildlife Refuge. This embayment experiences elevated bacterial concentration due to excess bacterial inputs from storm water runoff, nonpoint sources, and wash off from marshes due to tide and wind-induced set-up and set-down. Bacteria can also grow in the marsh and small tributaries. It is difficult to use a traditional watershed model to simulate bacterial loading, especially in this low-lying marsh area with abundant wildlife, while runoff is not solely driven by precipitation. An inverse approach is introduced to estimate loading from unknown sources based on observations in the embayment. The estimated loadings were combined with loadings estimated from different sources (human, wildlife, agriculture, pets, etc.) and input to the watershed model. The watershed model simulated long-term flow and bacterial loading and discharged to a three-dimensional transport model driven by tide, wind, and freshwater discharge. The transport model efficiently simulates the transport and fate of the bacterial concentration in the embayment and is capable of determining the loading reduction needed to improve the water quality condition of the embayment. Combining inverse, watershed, and transport models is a sound approach for simulating bacterial transport correctly in the coastal embayment with complex unknown bacterial sources, which are not solely driven by precipitation. Full article
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12639 KiB  
Article
Dynamic Reusable Workflows for Ocean Science
by Richard P. Signell, Filipe Fernandes and Kyle Wilcox
J. Mar. Sci. Eng. 2016, 4(4), 68; https://doi.org/10.3390/jmse4040068 - 25 Oct 2016
Cited by 1 | Viewed by 7575
Abstract
Digital catalogs of ocean data have been available for decades, but advances in standardized services and software for catalog searches and data access now make it possible to create catalog-driven workflows that automate—end-to-end—data search, analysis, and visualization of data from multiple distributed sources. [...] Read more.
Digital catalogs of ocean data have been available for decades, but advances in standardized services and software for catalog searches and data access now make it possible to create catalog-driven workflows that automate—end-to-end—data search, analysis, and visualization of data from multiple distributed sources. Further, these workflows may be shared, reused, and adapted with ease. Here we describe a workflow developed within the US Integrated Ocean Observing System (IOOS) which automates the skill assessment of water temperature forecasts from multiple ocean forecast models, allowing improved forecast products to be delivered for an open water swim event. A series of Jupyter Notebooks are used to capture and document the end-to-end workflow using a collection of Python tools that facilitate working with standardized catalog and data services. The workflow first searches a catalog of metadata using the Open Geospatial Consortium (OGC) Catalog Service for the Web (CSW), then accesses data service endpoints found in the metadata records using the OGC Sensor Observation Service (SOS) for in situ sensor data and OPeNDAP services for remotely-sensed and model data. Skill metrics are computed and time series comparisons of forecast model and observed data are displayed interactively, leveraging the capabilities of modern web browsers. The resulting workflow not only solves a challenging specific problem, but highlights the benefits of dynamic, reusable workflows in general. These workflows adapt as new data enter the data system, facilitate reproducible science, provide templates from which new scientific workflows can be developed, and encourage data providers to use standardized services. As applied to the ocean swim event, the workflow exposed problems with two of the ocean forecast products which led to improved regional forecasts once errors were corrected. While the example is specific, the approach is general, and we hope to see increased use of dynamic notebooks across geoscience domains. Full article
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12080 KiB  
Article
Assessment of Damage and Adaptation Strategies for Structures and Infrastructure from Storm Surge and Sea Level Rise for a Coastal Community in Rhode Island, United States
by Christopher Small, Tyler Blanpied, Alicia Kauffman, Conor O’Neil, Nicholas Proulx, Mathew Rajacich, Hailey Simpson, Jeffrey White, Malcolm L. Spaulding, Christopher D.P. Baxter and J. Craig Swanson
J. Mar. Sci. Eng. 2016, 4(4), 67; https://doi.org/10.3390/jmse4040067 - 20 Oct 2016
Cited by 8 | Viewed by 6627
Abstract
This paper presents an evaluation of inundation, erosion, and wave damage for a coastal community in Rhode Island, USA. A methodology called the Coastal Environmental Risk Index (CERI) was used that incorporates levels of inundation including sea level rise, wave heights using STWAVE, [...] Read more.
This paper presents an evaluation of inundation, erosion, and wave damage for a coastal community in Rhode Island, USA. A methodology called the Coastal Environmental Risk Index (CERI) was used that incorporates levels of inundation including sea level rise, wave heights using STWAVE, and detailed information about individual structures from an E911 database. This information was input into damage functions developed by the U.S. Army Corps of Engineers following Hurricane Sandy. Damage from erosion was evaluated separately from local published erosion rates. Using CERI, two different adaptation strategies were evaluated that included a combination of dune restoration, protective berms, and a tide gate. A total of 151 out of 708 structures were estimated to be protected from inundation and wave action by the combined measures. More importantly, the use of CERI allowed for the assessment of the impact of different adaptation strategies on both individual structures and an entire community in a Geographical Information Systems (GIS) environment. This tool shows promise for use by coastal managers to assess damage and mitigate risk to coastal communities. Full article
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2081 KiB  
Review
Matching Forces Applied in Underwater Hull Cleaning with Adhesion Strength of Marine Organisms
by Dinis Oliveira and Lena Granhag
J. Mar. Sci. Eng. 2016, 4(4), 66; https://doi.org/10.3390/jmse4040066 - 17 Oct 2016
Cited by 28 | Viewed by 8242
Abstract
Biofouling is detrimental to the hydrodynamic performance of ships. In spite of advances in hull coating technology, a ship must usually undergo underwater hull cleaning to remove biofouling during her in-service time. However, some cleaning practices may also lead to decreased lifetime of [...] Read more.
Biofouling is detrimental to the hydrodynamic performance of ships. In spite of advances in hull coating technology, a ship must usually undergo underwater hull cleaning to remove biofouling during her in-service time. However, some cleaning practices may also lead to decreased lifetime of the fouling-control coating. Therefore, cleaning forces should be minimized, according to the adhesion strength of marine organisms present on the hull. In this article, values of adhesion strength found in available literature are discussed in the light of current knowledge on hull cleaning technology. Finally, the following knowledge gaps are identified: (1) data on adhesion strength of naturally-occurring biofouling communities are practically absent; (2) shear forces imparted by current cleaning devices on low-form fouling (microfouling) and corresponding effects on hull coatings are largely unknown. This knowledge would be valuable for both developers and users of cleaning technology. Full article
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8120 KiB  
Article
Long-Term Morphological Modeling of Barrier Island Tidal Inlets
by Richard Styles, Mitchell E. Brown, Katherine E. Brutsché, Honghai Li, Tanya M. Beck and Alejandro Sánchez
J. Mar. Sci. Eng. 2016, 4(4), 65; https://doi.org/10.3390/jmse4040065 - 23 Sep 2016
Cited by 17 | Viewed by 6005
Abstract
The primary focus of this study is to apply a two-dimensional (2-D) coupled flow-wave-sediment modeling system to simulate the development and growth of idealized barrier island tidal inlets. The idealized systems are drawn from nine U.S. coastal inlets representing Pacific Coast, Gulf Coast [...] Read more.
The primary focus of this study is to apply a two-dimensional (2-D) coupled flow-wave-sediment modeling system to simulate the development and growth of idealized barrier island tidal inlets. The idealized systems are drawn from nine U.S. coastal inlets representing Pacific Coast, Gulf Coast and Atlantic Coast geographical and climatological environments. A morphological factor is used to effectively model 100 years of inlet evolution and the resulting morphological state is gauged in terms of the driving hydrodynamic processes. Overall, the model performs within the range of established theoretically predicted inlet cross-sectional area. The model compares favorably to theoretical models of maximum inlet currents, which serve as a measure of inlet stability. Major morphological differences are linked to inlet geometry and tidal forcing. Narrower inlets develop channels that are more aligned with the inlet axis while wider inlets develop channels that appear as immature braided channel networks similar to tidal flats in regions with abundant sediment supply. Ebb shoals with strong tidal forcing extend further from shore and spread laterally, promoting multi-lobe development bisected by ebb shoal channels. Ebb shoals with moderate tidal forcing form crescent bars bracketing a single shore-normal channel. Longshore transport contributes to ebb shoal asymmetry and provides bed material to help maintain the sediment balance in the bay. Full article
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4059 KiB  
Article
Statistical Interpolation of Tidal Datums and Computation of Its Associated Spatially Varying Uncertainty
by Lei Shi and Edward Myers
J. Mar. Sci. Eng. 2016, 4(4), 64; https://doi.org/10.3390/jmse4040064 - 22 Sep 2016
Cited by 3 | Viewed by 4333
Abstract
Tidal datums are key components in NOAA’s Vertical Datum transformation project (VDatum). In this paper, we propose a statistical interpolation method, derived from the variational principle, to calculate tidal datums by blending the modeled and the observed tidal datums. Through the implementation of [...] Read more.
Tidal datums are key components in NOAA’s Vertical Datum transformation project (VDatum). In this paper, we propose a statistical interpolation method, derived from the variational principle, to calculate tidal datums by blending the modeled and the observed tidal datums. Through the implementation of this statistical interpolation method in the Chesapeake and Delaware Bays, we conclude that the statistical interpolation method for tidal datums has great advantages over the currently used deterministic interpolation method. The foremost, and inherent, advantage of the statistical interpolation is its capability to integrate data from different sources and with different accuracies without concern for their relative spatial locations. The second advantage is that it provides a spatially varying uncertainty for the entire domain in which data is being integrated. The latter is especially helpful for the decision-making process of where new instruments would be most effectively placed. Lastly, the test case results show that the statistical interpolation reduced the bias, maximum absolute error, mean absolute error, and root mean square error in comparison to the current deterministic approach. Full article
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