Wave Energy Assessment in the Bohai Sea and the Yellow Sea Based on a 40-Year Hindcast

A wave hindcast, covering the period of 1979–2018, was preformed to assess wave energy potential in the Bohai Sea and the Yellow Sea. The hindcase was carried out using the third generation wave model TOMAWAC with high spatio-temporal resolution (about 1 km and on an hourly basis). Results show that the mean values of significant wave height increase from north to south, and the maximum values are located at the south part of the Yellow Sea with amplitude within 1.6 m. The magnitudes of significant wave height values vary significantly within seasons; they are at a maximum in winter. The wave energy potential was represented by distributions of the wave power flux. The largest values appear in the southeast part of the numerical domain with wave power flux values of 8 kW/m. The wave power flux values are less than 2 kW/m in the Bohai Sea and nearshore areas of the Yellow Sea. The seasonal mean wave power flux was found up to 8 kW/m in the winter and autumn. To investigate the exploitable wave energy, a wave energy event was defined based on the significant wave height (Hs) threshold values of 0.5 m. The wave energy in south part of the Yellow Sea is more steady and intensive than in the other areas. Wave energy in winter is more suitable for harvesting wave energy. Long-term trends of wave power availability suggest that the values of wave power slightly decreased in the 1990s, whereas they have been increasing since 2006.

Download Full-text

Study of Directional Declustering for Estimating Extreme Wave Heights in the Yellow Sea

Journal of Marine Science and Engineering ◽

10.3390/jmse8040236 ◽

2020 ◽

Vol 8 (4) ◽

pp. 236 ◽

Cited By ~ 1

Author(s):

Huijun Gao ◽

Zhuxiao Shao ◽

Guoxiang Wu ◽

Ping Li

Keyword(s):

Wave Height ◽

Yellow Sea ◽

Significant Wave Height ◽

Extreme Values ◽

The Yellow Sea ◽

Distribution Model ◽

Significant Wave ◽

Window Method ◽

Wave Heights ◽

Significant Wave Heights

The study of extreme waves is important for the protection of coastal and ocean structures. In this work, a 22-year (1990–2011) wave hindcast in the Yellow Sea is employed to perform the assessment of extreme significant wave heights in this area. To extract the independent sample from this database, the fixed window method is used, which takes the peak significant wave height within five d. With the selected samples, directional declustering is studied to extract the homogenous sample. The results show that most of the independent samples (especially large samples) are observed in the North. In this direction, the peak over threshold (POT) method is used to extract the extreme sample from the homogenous sample, and then the generalized Pareto distribution model is used to extrapolate the extreme significant wave height. In addition to this combination, the annual maxima method with the Gumbel model is also used for estimating extreme values. The comparisons show that the return significant wave heights of the first combination are reliable, resulting from a flexible sampling window in the POT method. With this conclusion, the extreme significant wave height is extrapolated from the Yellow Sea, which can be used to protect the structure in the main directional bin.

Download Full-text

Long-term assessment of wave energy in the China Sea using 30-year hindcast data

Energy Exploration & Exploitation ◽

10.1177/0144598719878777 ◽

2019 ◽

Vol 38 (1) ◽

pp. 37-56 ◽

Cited By ~ 2

Author(s):

Shaobo Yang ◽

Linlin Fan ◽

Shanhua Duan ◽

Chongwei Zheng ◽

Xingfei Li ◽

...

Keyword(s):

Power Density ◽

Wave Height ◽

Wave Energy ◽

Significant Wave Height ◽

Regional Distribution ◽

Wave Power ◽

Significant Wave ◽

China Sea ◽

Wave Power Density

In this study, a long-term assessment of the wave energy in the China Sea was performed for a 30-year time interval (1988–2017), using the model WAVEWATCH-III. The reliability of the wave simulation results was increased by means of longer time horizon data compared to other relevant studies in the China Sea. This analysis provided information on the regional distribution as well as on the monthly and seasonal variability. The exploitation and stability of wave energy were taken into consideration, so as to find the advantage of resource exploitation. Results indicated that values of significant wave height and wave power density had obviously differences compared with different months, especially in December with a maximum significant wave height of 2.7 m and 35 kW/m of wave power density. The minimum value of them appeared in May, was 1.0 m and 4.5 kW/m, respectively. The distribution of wave energy was abundant in winter and the poorest in summer. In winter, the significant wave height in most areas was above 1.8 m, while the maximum wave energy density in summer was only 1.2 m. As for the wave power density, in winter values in most areas were above 18 kW/m, while the maximum value in summer was only 12 kW/m. In sight of regional distribution, the highest wave energy potential was located in the Northern South China Sea, the East China Sea, the Ryukyu Islands waters, east of the Taiwan Island and the Luzon Strait, with coefficient of variation was within 2.0 and occurrence of exploitation was above 80%, whereas the Bohai Sea, the northern part of the Yellow sea, the Gulf of Thailand, and the Northern Bay were in poor contribution, with occurrence of exploitation was within 50%.

Download Full-text

Nitric oxide (NO) in the Bohai Sea and the Yellow Sea

Biogeosciences ◽

10.5194/bg-16-4485-2019 ◽

2019 ◽

Vol 16 (22) ◽

pp. 4485-4496 ◽

Cited By ~ 1

Author(s):

Ye Tian ◽

Chao Xue ◽

Chun-Ying Liu ◽

Gui-Peng Yang ◽

Pei-Feng Li ◽

...

Keyword(s):

Nitric Oxide ◽

Surface Layer ◽

Yellow Sea ◽

Bohai Sea ◽

Limit Of Detection ◽

Bottom Layer ◽

The Yellow Sea ◽

The Bohai Sea ◽

Significant Difference ◽

Average Flux

Abstract. Nitric oxide (NO) is a short-lived compound of the marine nitrogen cycle; however, our knowledge about its oceanic distribution and turnover is rudimentary. Here we present the measurements of dissolved NO in the surface and bottom layers at 75 stations in the Bohai Sea (BS) and the Yellow Sea (YS) in June 2011. Moreover, NO photoproduction rates were determined at 27 stations in both seas. The NO concentrations in the surface and bottom layers were highly variable and ranged from below the limit of detection (i.e., 32 pmol L−1) to 616 pmol L−1 in the surface layer and 482 pmol L−1 in the bottom layer. There was no significant difference (p>0.05) between the mean NO concentrations in the surface (186±108 pmol L−1) and bottom (174±123 pmol L−1) layers. A decreasing trend of NO in bottom-layer concentrations with salinity indicates a NO input by submarine groundwater discharge. NO in the surface layer was supersaturated at all stations during both day and night and therefore the BS and YS were a persistent source of NO to the atmosphere at the time of our measurements. The average flux was about 4.5×10-16 mol cm−2 s−1 and the flux showed significant positive relationship with the wind speed. The accumulation of NO during daytime was a result of photochemical production, and photoproduction rates were correlated to illuminance. The persistent nighttime NO supersaturation pointed to an unidentified NO dark production. NO sea-to-air flux densities were much lower than the NO photoproduction rates. Therefore, we conclude that the bulk of the NO produced in the mixed layer was rapidly consumed before its release to the atmosphere.

Download Full-text

Physical Modelling of the Effect on the Wave Field of the WaveCat Wave Energy Converter

Journal of Marine Science and Engineering ◽

10.3390/jmse9030309 ◽

2021 ◽

Vol 9 (3) ◽

pp. 309

Author(s):

James Allen ◽

Gregorio Iglesias ◽

Deborah Greaves ◽

Jon Miles

Keyword(s):

Wave Height ◽

Wave Energy ◽

Significant Wave Height ◽

Wedge Angle ◽

Wave Energy Converter ◽

Wave Period ◽

Surface Elevation ◽

Energy Converter ◽

Significant Wave ◽

Model Scale

The WaveCat is a moored Wave Energy Converter design which uses wave overtopping discharge into a variable v-shaped hull, to generate electricity through low head turbines. Physical model tests of WaveCat WEC were carried out to determine the device reflection, transmission, absorption and capture coefficients based on selected wave conditions. The model scale was 1:30, with hulls of 3 m in length, 0.4 m in height and a freeboard of 0.2 m. Wave gauges monitored the surface elevation at discrete points around the experimental area, and level sensors and flowmeters recorded the amount of water captured and released by the model. Random waves of significant wave height between 0.03 m and 0.12 m and peak wave periods of 0.91 s to 2.37 s at model scale were tested. The wedge angle of the device was set to 60°. A reflection analysis was carried out using a revised three probe method and spectral analysis of the surface elevation to determine the incident, reflected and transmitted energy. The results show that the reflection coefficient is highest (0.79) at low significant wave height and low peak wave period, the transmission coefficient is highest (0.98) at low significant wave height and high peak wave period, and absorption coefficient is highest (0.78) when significant wave height is high and peak wave period is low. The model also shows the highest Capture Width Ratio (0.015) at wavelengths on the order of model length. The results have particular implications for wave energy conversion prediction potential using this design of device.

Download Full-text

Accumulation and ecological risk of heavy metals in soils along the coastal areas of the Bohai Sea and the Yellow Sea: A comparative study of China and South Korea

Environment International ◽

10.1016/j.envint.2020.105519 ◽

2020 ◽

Vol 137 ◽

pp. 105519 ◽

Cited By ~ 5

Author(s):

Peng Liu ◽

Wenyou Hu ◽

Kang Tian ◽

Biao Huang ◽

Yongcun Zhao ◽

...

Keyword(s):

Heavy Metals ◽

South Korea ◽

Comparative Study ◽

Ecological Risk ◽

Yellow Sea ◽

Bohai Sea ◽

Coastal Areas ◽

The Yellow Sea ◽

The Bohai Sea ◽

Heavy Metals In Soils

Download Full-text

Characterization of Bacterial Communities in Bioaerosols over Northern Chinese Marginal Seas and the Northwestern Pacific Ocean in Spring

Journal of Applied Meteorology and Climatology ◽

10.1175/jamc-d-18-0142.1 ◽

2019 ◽

Vol 58 (4) ◽

pp. 903-917 ◽

Cited By ~ 2

Author(s):

Manman Ma ◽

Yu Zhen ◽

Tiezhu Mi

Keyword(s):

Pacific Ocean ◽

Yellow Sea ◽

Bacterial Communities ◽

Bohai Sea ◽

The Yellow Sea ◽

Northwestern Pacific ◽

Particle Sizes ◽

Marine Aerosols ◽

Northwestern Pacific Ocean ◽

The Bohai Sea

AbstractStudies of the community structures of bacteria in marine aerosols of different particle sizes have not been reported. Aerosol samples were collected using a six-stage bioaerosol sampler over the Bohai Sea, the Yellow Sea, and northwestern Pacific Ocean in the spring of 2014. The diversity and composition of these samples were investigated by Illumina high-throughput sequencing, and 130 genera were detected in all of the samples; the most abundant bacterial genus was Bacteroides, followed by Prevotella and Megamonas. The Chao1 and Shannon diversity indices ranged from 193 to 1044 and from 5.44 to 8.33, respectively. The bacterial community structure in coarse particles (diameter larger than 2.1 μm) was more complex and diverse than that in fine particles (diameter less than 2.1 μm) in marine bioaerosols from over the Yellow Sea and northwestern Pacific Ocean, while the opposite trend was observed for samples collected over the Bohai Sea. Although we were sampling over marine regions, the sources of the bioaerosols were mostly continental. Temperature and wind speed significantly influenced the bacterial communities in marine aerosols of different particle sizes. There may be a bacterial background in the atmosphere in the form of several dominant taxa, and the bacterial communities are likely mixed constantly during transmission.

Download Full-text

Occurrence and distribution of marine natural organic pollutants: Lipophilic marine algal toxins in the Yellow Sea and the Bohai Sea, China

The Science of The Total Environment ◽

10.1016/j.scitotenv.2017.08.304 ◽

2018 ◽

Vol 612 ◽

pp. 931-939 ◽

Cited By ~ 15

Author(s):

Junhui Chen ◽

Tongzhu Han ◽

Xiaotong Li ◽

Xiuping He ◽

Yanlong Wang ◽

...

Keyword(s):

Organic Pollutants ◽

Yellow Sea ◽

Bohai Sea ◽

The Yellow Sea ◽

Algal Toxins ◽

The Bohai Sea ◽

Marine Algal

Download Full-text

Performance of Linear Generator Designs for Direct Drive Wave Energy Converter under Unidirectional Long-Crested Random Waves

Energies ◽

10.3390/en14165098 ◽

2021 ◽

Vol 14 (16) ◽

pp. 5098

Author(s):

Budi Azhari ◽

Fransisco Danang Wijaya ◽

Edwar Yazid

Keyword(s):

Output Power ◽

Wave Height ◽

Wave Energy ◽

Significant Wave Height ◽

Analytical Calculation ◽

Weight Ratio ◽

Peak Frequency ◽

Random Waves ◽

Direct Drive ◽

Significant Wave

For generating electricity, direct-drive wave energy converters (WECs) with linear permanent magnet generators (LPMGs) have advantages in terms of efficiency, simplicity, and force-to-weight ratio over WEC with rotary generators. However, the converter’s work under approaching-real wave conditions should be investigated. This paper studies the performance of a pico-scale WEC with two different LPMGs under unidirectional long-crested random waves. Different significant wave heights (using data in the Southern Ocean of Yogyakarta, Indonesia) and peak frequencies are tested. The JONSWAP energy spectrum is used to extract the wave elevations, while the MSS toolbox in MATLAB Simulink is employed to solve the floater’s dynamic responses. Next, the translator movements are extracted and combined with the flux distribution from FEMM simulation and analytical calculation, and the output powers are obtained. An experiment is conducted to test the output under constant speed. The results show for both designs, different tested significant wave height values produce higher output powers than peak frequency variation, but there is no specific trend on them. Meanwhile, the peak frequency is inversely proportional to the output power. Elimination of the non-facing events results in increasing output power under both parameters’ variation, with higher significant wave height resulting in a bigger increase. The semi iron-cored LPMG produces lower power loss and higher efficiency.

Download Full-text

The silica-carbon biogeochemical cycle in the Bohai Sea and its responses to the changing terrestrial loadings

10.5194/bg-2016-42 ◽

2016 ◽

Author(s):

Jun Liu ◽

Lex Bouwman ◽

Jiaye Zang ◽

Chenying Zhao ◽

Xiaochen Liu ◽

...

Keyword(s):

Primary Production ◽

Water Column ◽

Yellow Sea ◽

Bohai Sea ◽

Critical Role ◽

The Yellow Sea ◽

Organic C ◽

Riverine Input ◽

The Bohai Sea ◽

River Loads

Abstract. Silicon (Si) and carbon (C) play key roles in the river and marine biogeochemistry. The Si and C budgets for the Bohai Sea were established on the basis of measurements at a range of stations and additional data from the literature. The results show that the spatial distributions of reactive Si and organic C (OC) in the water column are largely affected by the riverine input, primary production and export to the Yellow Sea. Biogenic silica (BSi) and total OC in sediments are mainly from marine primary production. The major supply of dissolved silicate (DSi) comes from benthic diffusion, riverine input alone accounts for 17 % of reactive Si inputs to the Bohai Sea; the dominant DSi removal from the water column is diatom uptake, followed by sedimentation. Rivers contribute 47 % of exogenous OC inputs to the Bohai Sea; the dominant outputs of OC are sedimentation and export to the Yellow Sea. The net burial of BSi and OC represent 3.3 % and 1.0 % of total primary production, respectively. Primary production has increased by 10 % since 2002 as a result of increased river loads of DSi and BSi. Our findings underline the critical role of riverine Si supply in primary production in coastal marine ecosystems.

Download Full-text