The tell tail is usually placed on the triangular sail to display the running state of the air flow on the sail surface.It is of great significance to make accurate judgement on the drift of the tell tail of the sailb...The tell tail is usually placed on the triangular sail to display the running state of the air flow on the sail surface.It is of great significance to make accurate judgement on the drift of the tell tail of the sailboat during sailing for the best sailing effect.Normally it is difficult for sailors to keep an eye for a long time on the tell sail for accurate judging its changes,affected by strong sunlight and visual fatigue.In this case,we adopt computer vision technology in hope of helping the sailors judge the changes of the tell tail in ease with ease.This paper proposes for the first time a method to classify sailboat tell tails based on deep learning and an expert guidance system,supported by a sailboat tell tail classification data set on the expert guidance system of interpreting the tell tails states in different sea wind conditions,including the feature extraction performance.Considering the expression capabilities that vary with the computational features in different visual tasks,the paper focuses on five tell tail computing features,which are recoded by an automatic encoder and classified by a SVM classifier.All experimental samples were randomly divided into five groups,and four groups were selected from each group as the training set to train the classifier.The remaining one group was used as the test set for testing.The highest resolution value of the ResNet network was 80.26%.To achieve better operational results on the basis of deep computing features obtained through the ResNet network in the experiments.The method can be used to assist the sailors in making better judgement about the tell tail changes during sailing.展开更多
In the present study, an existing three-dimensional finite volume computational ocean model （FVCOM） was refined and configured including an algorithm for computing the power density and mean power density at Qiongzh...In the present study, an existing three-dimensional finite volume computational ocean model （FVCOM） was refined and configured including an algorithm for computing the power density and mean power density at Qiongzhou Strait of China. The refined model was validated with the measured tidal levels and tidal currents at different gauging stations. The model results are in reasonable agreement with the measured data. Based on the modeling results, we assess the resource of the tidal stream energy in the Qiongzhou Strait and discuss the temporal and the spatial distribution of the tidal current energy there. The conclusion is extracted： the higher power density occurs in the middle area of the strait, and lower at both sides. Characteristics of power density such as the maximum possibility speed, maximum power density during the spring tide period and the neap tide period, have the similar distribution. The southeast part and central area of the strait are of rich tidal current energy, where the maximum possibility speed can reach to 4.6 m/s, and the maximum power density of the spring tide period and the neap tide period can reach 5 996 and 467 W/mz separately in the surface layer The annual mean power density can reach 819 W/m2. Statistical length of accumulative time of the velocity exceeding 0.7 m/s is about 4 717 h at local point during a year. The total theoretical tidal current energy resource is approximately 189.55 MW and the available exploited energy on present technology condition is 249, 20.2 and 263 GW/a separately by using the methods FLUX, FARM and GC in the Qiongzhou Strait.展开更多
We developed a Global Ocean Circulation and Tide Model （GOCTM） with coarse grids in the open deep ocean degrading ‘smoothly’ into the highly resolved China Seas （CS） of refined grids to study the tides and circu...We developed a Global Ocean Circulation and Tide Model （GOCTM） with coarse grids in the open deep ocean degrading ‘smoothly’ into the highly resolved China Seas （CS） of refined grids to study the tides and circulation there.GOCTM is based on the framework of the Finite Volume approach for better mass conservation through improved transports across the discrete individual control volume.It also takes a full advantage of the geometric flexibility of unstructured mesh using a realistic global topography including the Arctic Ocean.The CS are given a special focus by refining the unstructured grids,but they are embedded into global domain naturally.Furthermore,GOCTM not only successfully avoids the treatment of the open boundaries,but also optimizes the trade-off between computational cost and model accuracy.Meanwhile,GOCTM is driven by the astronomical tide-generating potential and the secondary tide-generating potential directly,together with the wind stress and heat flux.GOCTM succeeds in reproducing the global eight principal tidal harmonic constants.Particularly,the simulated tidal results in the CS are improved compared to some other regional models with the discrepancy of 3.9 cm for M 2 tide.This idea of GOCTM can also be referred for other regional ocean study.展开更多
The Shacheng Bay （SCB） is one of the most complex coastal bays in southeast China and due to the fact of complicated geometry and dynamic coastal processes, it is considered as a challenging area for the nu- merical...The Shacheng Bay （SCB） is one of the most complex coastal bays in southeast China and due to the fact of complicated geometry and dynamic coastal processes, it is considered as a challenging area for the nu- merical simulation of its hydrodynamic characteristics. The most advanced finite volume ocean model, fi- nite-volume coastal ocean model （FVCOM）, has adopted to simulate this hydrodynamic system, where tidal currents, tidal residual current and dye diffusion processes were studied and analyzed quantitatively. The validation of this numerical model matches well with various observation data, including elevation and current data. The misfit of a tidal elevation has a relative standard error of 3.66% and 4.67% for M2 and S2 tide components. The current validation shows a good match with an average error of 10 cm/s and 8° in the speed major axis and its direction respectively between the simulation and the measurement. This proves the robustness and reliability of this model. It is also found that the cape effect is significant and important in this system. The dye diffusion simulations show a 53 d flushing period for the whole inner bay waterbody. The results are of its first kind for understanding the hydrodynamic system in the SCB and they can provide helnful and trustful scientific information for others.展开更多
Based on the comprehensive collection of the field observed salinity of the Bohai Sea （BHS） and the northern Huanghai Sea （NHS） from the 1950s to the present, the patterns of 10-years-averaged salinity at the diff...Based on the comprehensive collection of the field observed salinity of the Bohai Sea （BHS） and the northern Huanghai Sea （NHS） from the 1950s to the present, the patterns of 10-years-averaged salinity at the different layers in the recent five decades （the 1950s, the 1960s, the 1970s, the 1980s and the 1990s） are obtained by the spatial-temporal interpolation technique with the scrupulous data quality control in this study. Then, by combining the spatial-temporal interpolation technique with successive correction method, the annual distributions of salinity both in the BHS and in the NHS are obtained as well. The data analyses indicate that the overall salinity in the BHS and the NHS increases from the 1960s till the present, with the increase of annual mean salinity of 0.04 psu from the 1950s, and the maximum increase rate of salinity is about 0.14 psu/a in the Bohai Bay. The high salinity tongue extended significantly from the NHS into the BHS. The intensified eastern wind field is related to the western intrusion of the NHS warm current, which probably leads to the moving forward of the high salinity water mass into the BHS. However, it is rather different from the salinity distribution characteristics between the 1950s and the 1960s. The extensive precipitation in the 1960s could lead to an increase in the discharge of the Huanghe River, which might result in the decrease of salinity in the BHS. But the salinity isoline of 32 in the NHS still extended significantly into the BHS in the 1960s. Since the 1980s, the patterns of salinity distribution have changed thoroughly. The salinity in the central area of the BHS was low, while the salinity in the Bohai Bay and the Liaodong Bay was higher than the other regions with its horizontal salinity gradient decreasing in the 1980s. The Empirical Orthogonal Function Analysis （EOF） is also conducted to study the interannual salinity variability of the BHS and the NHS. The correlation coefficient between the time coefficient series of the main mode and the Huanghe River discharge can reach-64.57%. It can be concluded that salinity variation of the BHS and the NHS has strong negative correlation with the Huanghe River discharge.展开更多
The Wenzhou Shoal Reclamation Project is the core part of Wenzhou Peninsula Engineering which is a big comprehensive development project to expand the city space. The dynamics of the surrounding area was proved to suf...The Wenzhou Shoal Reclamation Project is the core part of Wenzhou Peninsula Engineering which is a big comprehensive development project to expand the city space. The dynamics of the surrounding area was proved to suffer little effect in response to the Lingni north dyke since it was built approximately along the current direction. Therefore, this paper focuses firstly on the tidal characteristics in the Wenzhou and Yueqing bays with the Lingni north dyke being built and then on the changes resulting from the implementation of the on-going Wenzhou Shoal Reclamation Project(WSRP) which will reclaim land from the whole Wenzhou Shoal. To simulate the tidal dynamics, a high-resolution coastal ocean model with unstructured triangular grids was set up for the Wenzhou and Yueqing Bays. The model resolved the complicated tidal dynamics with the simulated tidal elevation and current in good agreement with observations. In the study area, M2 is the predominant tidal component, which means the tide is semidiurnal. The new reclamation project hardly affects the Yueqing Bay and the open ocean, but there are concentrated effects on the mouth of the southern branch of the Oujiang River and the southwest of Wenzhou Shoal. This study provides an indicative reference to the local government and helps to weigh the advantages and disadvantages of the project.展开更多
An unstructured model FVCOM(The Unstructured Grid Finite Volume Community Ocean Model)with sink momentum term was applied to simulate the tidal current field in Zhoushan Archipelago,China,with focus on the region name...An unstructured model FVCOM(The Unstructured Grid Finite Volume Community Ocean Model)with sink momentum term was applied to simulate the tidal current field in Zhoushan Archipelago,China,with focus on the region named PuHu Channel between Putuo Island and Hulu Island.The model was calibrated with several measurements in the channel,and the model perform-ance was validated.An examination of the spatial and temporal distributions of tidal energy resources based on the numerical simula-tion revealed that the greatest power density of tidal energy during spring tide is 3.6kWm^(−2)at the northern area of the channel.Two parameters were introduced to characterize the generation duration of the tidal array that causes the temporal variation of tidal current energy.The annual average available energy in the channel was found to be approximately 2.6MW.The annual generating hours at rated power was found to be 1800 h when the installed capacity of tidal array is approximately 12MW.A site for the tidal array with 25 turbines was selected,and the layout of the array was configured based on the EMEC specifications.Hydrodynamic influence due to the deployment of the tidal array was simulated by the modified FVCOM model.The simulation showed that the tidal level did not significantly change because of the operation of the tidal array.The velocity reduction covered a 2km^(2)area of the downstream the tidal array,with a maximum velocity reduction of 8cms−1 at mid-flood tide,whereas the streamwise velocity on both sides of the farm increased slightly.展开更多
基金supported by the Shandong Provin-cial Key Research Project of Undergraduate Teaching Reform(No.Z2022218)the Fundamental Research Funds for the Central University(No.202113028)+1 种基金the Graduate Education Promotion Program of Ocean University of China(No.HDJG20006)supported by the Sailing Laboratory of Ocean University of China.
文摘The tell tail is usually placed on the triangular sail to display the running state of the air flow on the sail surface.It is of great significance to make accurate judgement on the drift of the tell tail of the sailboat during sailing for the best sailing effect.Normally it is difficult for sailors to keep an eye for a long time on the tell sail for accurate judging its changes,affected by strong sunlight and visual fatigue.In this case,we adopt computer vision technology in hope of helping the sailors judge the changes of the tell tail in ease with ease.This paper proposes for the first time a method to classify sailboat tell tails based on deep learning and an expert guidance system,supported by a sailboat tell tail classification data set on the expert guidance system of interpreting the tell tails states in different sea wind conditions,including the feature extraction performance.Considering the expression capabilities that vary with the computational features in different visual tasks,the paper focuses on five tell tail computing features,which are recoded by an automatic encoder and classified by a SVM classifier.All experimental samples were randomly divided into five groups,and four groups were selected from each group as the training set to train the classifier.The remaining one group was used as the test set for testing.The highest resolution value of the ResNet network was 80.26%.To achieve better operational results on the basis of deep computing features obtained through the ResNet network in the experiments.The method can be used to assist the sailors in making better judgement about the tell tail changes during sailing.
基金The Chinese Marine Renewable Energy Special Fund under contract Nos GHME2012ZC05 and GHME2013ZC03
文摘In the present study, an existing three-dimensional finite volume computational ocean model （FVCOM） was refined and configured including an algorithm for computing the power density and mean power density at Qiongzhou Strait of China. The refined model was validated with the measured tidal levels and tidal currents at different gauging stations. The model results are in reasonable agreement with the measured data. Based on the modeling results, we assess the resource of the tidal stream energy in the Qiongzhou Strait and discuss the temporal and the spatial distribution of the tidal current energy there. The conclusion is extracted： the higher power density occurs in the middle area of the strait, and lower at both sides. Characteristics of power density such as the maximum possibility speed, maximum power density during the spring tide period and the neap tide period, have the similar distribution. The southeast part and central area of the strait are of rich tidal current energy, where the maximum possibility speed can reach to 4.6 m/s, and the maximum power density of the spring tide period and the neap tide period can reach 5 996 and 467 W/mz separately in the surface layer The annual mean power density can reach 819 W/m2. Statistical length of accumulative time of the velocity exceeding 0.7 m/s is about 4 717 h at local point during a year. The total theoretical tidal current energy resource is approximately 189.55 MW and the available exploited energy on present technology condition is 249, 20.2 and 263 GW/a separately by using the methods FLUX, FARM and GC in the Qiongzhou Strait.
基金The Hi-tech Research and Development Program (863) of China under contract No.2007AA09Z117the National Key Technology R&D Program under contract No.2011BAC03B02+1 种基金the National Natural Science Fund of China under contract No.40976001the National Marine Renewable Energy Program under contract Nos GHME2010ZC08,No.GHME 2010ZC11 and No.GHME2010ZC01
文摘We developed a Global Ocean Circulation and Tide Model （GOCTM） with coarse grids in the open deep ocean degrading ‘smoothly’ into the highly resolved China Seas （CS） of refined grids to study the tides and circulation there.GOCTM is based on the framework of the Finite Volume approach for better mass conservation through improved transports across the discrete individual control volume.It also takes a full advantage of the geometric flexibility of unstructured mesh using a realistic global topography including the Arctic Ocean.The CS are given a special focus by refining the unstructured grids,but they are embedded into global domain naturally.Furthermore,GOCTM not only successfully avoids the treatment of the open boundaries,but also optimizes the trade-off between computational cost and model accuracy.Meanwhile,GOCTM is driven by the astronomical tide-generating potential and the secondary tide-generating potential directly,together with the wind stress and heat flux.GOCTM succeeds in reproducing the global eight principal tidal harmonic constants.Particularly,the simulated tidal results in the CS are improved compared to some other regional models with the discrepancy of 3.9 cm for M 2 tide.This idea of GOCTM can also be referred for other regional ocean study.
基金The National Marine Renewable Energy Programs of China under contract Nos GHME2011ZC03,GHME2011GD01,GHME2012ZC02,GHME2012ZC03,GHME2012ZC05 and GHME2013ZC01the National Natural Science Foundation of China under contract No.41406011+5 种基金the Doctoral Fund of Ministry of Education of China under contract No.20120132120016the Shandong Province Natural Science Foundation of China under contract No.ZR2012DQ008the Strategic Priority Research Program of the Chinese Academy of Sciences under contract No.XDA11010201the Open Laboratory Fund of North China Sea Branch of State Oceanic Administration under contract No.2012012the Fundamental Research Funds for the Central Universities under contract No.201262004the Public Science and Technology Research Funds Projects of Ocean under contract No.201305030
文摘The Shacheng Bay （SCB） is one of the most complex coastal bays in southeast China and due to the fact of complicated geometry and dynamic coastal processes, it is considered as a challenging area for the nu- merical simulation of its hydrodynamic characteristics. The most advanced finite volume ocean model, fi- nite-volume coastal ocean model （FVCOM）, has adopted to simulate this hydrodynamic system, where tidal currents, tidal residual current and dye diffusion processes were studied and analyzed quantitatively. The validation of this numerical model matches well with various observation data, including elevation and current data. The misfit of a tidal elevation has a relative standard error of 3.66% and 4.67% for M2 and S2 tide components. The current validation shows a good match with an average error of 10 cm/s and 8° in the speed major axis and its direction respectively between the simulation and the measurement. This proves the robustness and reliability of this model. It is also found that the cape effect is significant and important in this system. The dye diffusion simulations show a 53 d flushing period for the whole inner bay waterbody. The results are of its first kind for understanding the hydrodynamic system in the SCB and they can provide helnful and trustful scientific information for others.
基金The Hi-tech Research and Development Program(863 Program) of China under contract No2007AA09Z117comprehensive Survey and Assessment of China’s Coastal Sea Program(China ‘908’ Project) under contract No908-01-ST02China "973" Program under contract No 2005CB422302
文摘Based on the comprehensive collection of the field observed salinity of the Bohai Sea （BHS） and the northern Huanghai Sea （NHS） from the 1950s to the present, the patterns of 10-years-averaged salinity at the different layers in the recent five decades （the 1950s, the 1960s, the 1970s, the 1980s and the 1990s） are obtained by the spatial-temporal interpolation technique with the scrupulous data quality control in this study. Then, by combining the spatial-temporal interpolation technique with successive correction method, the annual distributions of salinity both in the BHS and in the NHS are obtained as well. The data analyses indicate that the overall salinity in the BHS and the NHS increases from the 1960s till the present, with the increase of annual mean salinity of 0.04 psu from the 1950s, and the maximum increase rate of salinity is about 0.14 psu/a in the Bohai Bay. The high salinity tongue extended significantly from the NHS into the BHS. The intensified eastern wind field is related to the western intrusion of the NHS warm current, which probably leads to the moving forward of the high salinity water mass into the BHS. However, it is rather different from the salinity distribution characteristics between the 1950s and the 1960s. The extensive precipitation in the 1960s could lead to an increase in the discharge of the Huanghe River, which might result in the decrease of salinity in the BHS. But the salinity isoline of 32 in the NHS still extended significantly into the BHS in the 1960s. Since the 1980s, the patterns of salinity distribution have changed thoroughly. The salinity in the central area of the BHS was low, while the salinity in the Bohai Bay and the Liaodong Bay was higher than the other regions with its horizontal salinity gradient decreasing in the 1980s. The Empirical Orthogonal Function Analysis （EOF） is also conducted to study the interannual salinity variability of the BHS and the NHS. The correlation coefficient between the time coefficient series of the main mode and the Huanghe River discharge can reach-64.57%. It can be concluded that salinity variation of the BHS and the NHS has strong negative correlation with the Huanghe River discharge.
基金supported by the National Basic Research Program of China(Grant no.2010CB428704)the National Nature Science Foundation of China(Grand nos.4127608341430963)
文摘The Wenzhou Shoal Reclamation Project is the core part of Wenzhou Peninsula Engineering which is a big comprehensive development project to expand the city space. The dynamics of the surrounding area was proved to suffer little effect in response to the Lingni north dyke since it was built approximately along the current direction. Therefore, this paper focuses firstly on the tidal characteristics in the Wenzhou and Yueqing bays with the Lingni north dyke being built and then on the changes resulting from the implementation of the on-going Wenzhou Shoal Reclamation Project(WSRP) which will reclaim land from the whole Wenzhou Shoal. To simulate the tidal dynamics, a high-resolution coastal ocean model with unstructured triangular grids was set up for the Wenzhou and Yueqing Bays. The model resolved the complicated tidal dynamics with the simulated tidal elevation and current in good agreement with observations. In the study area, M2 is the predominant tidal component, which means the tide is semidiurnal. The new reclamation project hardly affects the Yueqing Bay and the open ocean, but there are concentrated effects on the mouth of the southern branch of the Oujiang River and the southwest of Wenzhou Shoal. This study provides an indicative reference to the local government and helps to weigh the advantages and disadvantages of the project.
基金This work was supported by the National Key R&D Program of China(Nos.2019YFE0102500,2019YFB1504401,2019YFE0102500 and 2016YFC1401800).The au-thors would like to thank the FVCOM Development Group for their modeling support.
文摘An unstructured model FVCOM(The Unstructured Grid Finite Volume Community Ocean Model)with sink momentum term was applied to simulate the tidal current field in Zhoushan Archipelago,China,with focus on the region named PuHu Channel between Putuo Island and Hulu Island.The model was calibrated with several measurements in the channel,and the model perform-ance was validated.An examination of the spatial and temporal distributions of tidal energy resources based on the numerical simula-tion revealed that the greatest power density of tidal energy during spring tide is 3.6kWm^(−2)at the northern area of the channel.Two parameters were introduced to characterize the generation duration of the tidal array that causes the temporal variation of tidal current energy.The annual average available energy in the channel was found to be approximately 2.6MW.The annual generating hours at rated power was found to be 1800 h when the installed capacity of tidal array is approximately 12MW.A site for the tidal array with 25 turbines was selected,and the layout of the array was configured based on the EMEC specifications.Hydrodynamic influence due to the deployment of the tidal array was simulated by the modified FVCOM model.The simulation showed that the tidal level did not significantly change because of the operation of the tidal array.The velocity reduction covered a 2km^(2)area of the downstream the tidal array,with a maximum velocity reduction of 8cms−1 at mid-flood tide,whereas the streamwise velocity on both sides of the farm increased slightly.
