In this paper, ECOMSED (Estuarine Coastal Ocean Model with sediment transport) model is employed to simulate storm surge process caused by typhoon passing across East China Sea in nearly years. Capability of ECOMSED...In this paper, ECOMSED (Estuarine Coastal Ocean Model with sediment transport) model is employed to simulate storm surge process caused by typhoon passing across East China Sea in nearly years. Capability of ECOMSED to simulate storm surge is validated by comparing model result with observed data. Sensitivity experiments are designed to study the influence of sea level rise on typhoon storm surge. Numerical experiment shows that influence of mean sea level rise on typhoon storm surge is non-uniform spatially and changes as typhoon process differs. Maybe fixed boundary method would weaken the influence of mean sea level rise on storm surge, and free boundary method is suggested for the succeeding study.展开更多
Recently, as the oceanic activities are more and more frequently carried out, marine oil spill accidents bring to enormous harm to the economy and society in China, especially in the Offshore China. Marine oil spill i...Recently, as the oceanic activities are more and more frequently carried out, marine oil spill accidents bring to enormous harm to the economy and society in China, especially in the Offshore China. Marine oil spill is one kind of serious disasters which severely damages the marine environment. Aiming at the improvement of the emergency response system and response ability for the oil spill, the relative technologies on oil spill response are developed. This paper briefly introduces the developments and achievements of the oil spill numerical models, including the oil spill spreading model, the oil spill transport model, the oil particle model as well as the oil spill weathering model, which provide the theoretic criterions for the future work on the oil spill predicting and response.展开更多
Sea level seasonal variations in the east of China seas from 2004 to 2006 are simulated by the advanced ROMS model. The results show similar sea level spatial features with TOPEX/Poseidon observations, with annual ran...Sea level seasonal variations in the east of China seas from 2004 to 2006 are simulated by the advanced ROMS model. The results show similar sea level spatial features with TOPEX/Poseidon observations, with annual ranges decreasing gradually from the sea coast to the Kuroshio region. By getting rid of wind stress in ROMS model, the simulated sea level results still show obvious seasonal variations. However, the phenomenon of sea level anomaly disappears in Min Zhe Current Coastwise (MZCF) and Su Bei current coastwise (SBCF), and the change of it from coastal area to ocean recedes. The seal level difference between Bohai, Yellow Sea (BYS) and East China Sea (ECS) becomes weaker in spring and autumn. The annual differences decrease obviously, and the gradual change of annual ranges from seacoast to the Kuroshio almost disappears. The annual ranges in BYS are nearly identical. The annual range ratio without the wind stress to with the wind stress increases gradually from the sea coast to Kuroshio region.展开更多
For understanding more about the water exchange between the Kuroshio and the East China Sea,We studied the variability of the Kuroshio in the East China Sea(ECS) in the period of 1991 to 2008 using a three-dimensional...For understanding more about the water exchange between the Kuroshio and the East China Sea,We studied the variability of the Kuroshio in the East China Sea(ECS) in the period of 1991 to 2008 using a three-dimensional circulation model,and calculated Kuroshio onshore volume transport in the ECS at the minimum of 0.48 Sv(1 Sv ;106 m3/s) in summer and the maximum of 1.69 Sv in winter.Based on the data of WOA05 and NCEP,The modeled result indicates that the Kuroshio transport east of Taiwan Island decreased since 2000.Lateral movements tended to be stronger at two ends of the Kuroshio in the ECS than that of the middle segment.In addition,we applied a spectral mixture model(SMM) to determine the exchange zone between the Kuroshio and the shelf water of the ECS.The result reveals a significantly negative correlation(coefficient of-0.78) between the area of exchange zone and the Kuroshio onshore transport at 200 m isobath in the ECS.This conclusion brings a new view for the water exchange between the Kuroshio and the East China Sea.Additional to annual and semi-annual signals,intra-seasonal signal of probably the Pacific origin may trigger the events of Kuroshio intrusion and exchange in the ECS.展开更多
Quantified risk assessment(QRA) needs mathematicization of risk theory.However,attention has been paid almost exclusively to applications of assessment methods,which has led to neglect of research into fundamental the...Quantified risk assessment(QRA) needs mathematicization of risk theory.However,attention has been paid almost exclusively to applications of assessment methods,which has led to neglect of research into fundamental theories,such as the relationships among risk,safety,danger,and so on.In order to solve this problem,as a first step,fundamental theoretical relationships about risk and risk management were analyzed for this paper in the light of mathematics,and then illustrated with some charts.Second,man-machine-environment-management(MMEM) theory was introduced into risk theory to analyze some properties of risk.On the basis of this,a three-dimensional model of risk management was established that includes:a goal dimension;a management dimension;an operation dimension.This goal management operation(GMO) model was explained and then emphasis was laid on the discussion of the risk flowchart(operation dimension),which lays the groundwork for further study of risk management and qualitative and quantitative assessment.Next,the relationship between Formal Safety Assessment(FSA) and Risk Management was researched.This revealed that the FSA method,which the international maritime organization(IMO) is actively spreading,comes from Risk Management theory.Finally,conclusion were made about how to apply this risk management method to concrete fields efficiently and conveniently,as well as areas where further research is required.展开更多
The spatial pattern of urbanization in the Shanghai metropolitan area is quantified with GIS-based land use data set and gradient analysis of landscape metrics. A number of landscape metrics were computed along a 64 I...The spatial pattern of urbanization in the Shanghai metropolitan area is quantified with GIS-based land use data set and gradient analysis of landscape metrics. A number of landscape metrics were computed along a 64 Ion long and 6 km wide west-east transect and another 66 km long and 6 km wide south-north transect. The results of transect analysis with class-level metrics showed that the spatial pattern of urbanization could be reliably quantified using landscape metrics with a gradient analysis approach, and the location of the urbanization center could be identified precisely and consistently with multiple indices of the landscape metrics used in this study. Different land use types exhibited distinctive, but not necessarily unique, spatial signatures that were dependent on specific landscape metrics. These results seemed to characterize the urban core of the Shanghai metropolitan area rather accurately and precisely.. Agriculture patches were abundant and less fragmented; the urban land use types were extensive, having many small patches and highly fragmented.展开更多
This paper explores the potential to improve the impervious surface estimation accuracy using a multi-stage approach on the basis of vegetation-impervious surface-soil (V-I-S) model. In the first stage of Spectral Mix...This paper explores the potential to improve the impervious surface estimation accuracy using a multi-stage approach on the basis of vegetation-impervious surface-soil (V-I-S) model. In the first stage of Spectral Mixture Analysis (SMA) process, pixel purity index, a quantitative index for defining endmember quality, and a 3-dimensional endmember selection method were applied to refining endmembers. In the second stage, instead of obtaining impervious surface fraction by adding high and low albedo fractions directly, a linear regression model was built between impervious surface and high/low albedo using a random sampling method. The urban impervious surface distribution in the urban central area of Shanghai was predicted by the linear regression model. Estimation accuracy of spectral mixture analysis and impervious surface fraction were assessed using root mean square (RMS) and color aerial photography respectively. In comparison with three different research methods, this improved estimation method has a higher overall accuracy than traditional Linear Spectral Mixture Analysis (LSMA) method and the normalized SMA model both in root mean square error (RMSE) and standard error (SE). However, the model has a tendency to overestimate the impervious surface distribution.展开更多
Hazard factors, hazard-bearling objects, disaster-developing environment, and disaster-preventing capability play key roles in the formation of Tropical Cyclone (TC) disasters. Of all of these, the most important is...Hazard factors, hazard-bearling objects, disaster-developing environment, and disaster-preventing capability play key roles in the formation of Tropical Cyclone (TC) disasters. Of all of these, the most important is the intensity of hazard factors (risk sources). In this study, this intensity is uniformly defined by the probability of hazard factors; then a relationship is established between disaster risk intensity and hazard factors. The exceedance probability of various hazard factors, including frequency and timing, scope of wind and rain, and maximum wind and rain of impacting TC cases, are calculated using data from TCs that impacted Shanghai fi'om 1959-2006. The relationship between disaster situation and risk probability of hazard factors is analyzed, and the indices and model of TC disaster assessment are established based on the results. The process maximum wind speed and maximum daily precipitation are very important in TC-related disaster formation in Shanghai. The results of disaster indices coordinate with the results of the assessment model, and both can show the extent of probability of a TC disaster. Tests using TC data in 2007 and 2008 show that disasters caused by TC Krosa (0716) would be more serious than those by TC Wipha (0713), and that TC Fung Wong (0808) would have a weak impact. Real-life situations validate these results.展开更多
The wave-forcing 'Coriolis-Stokes forcing' and 'Stokes-vortex force' induced by Stokes drift affect the upper ocean jointly.To study the effect of the wave-induced Stokes drift on the dynamics of the o...The wave-forcing 'Coriolis-Stokes forcing' and 'Stokes-vortex force' induced by Stokes drift affect the upper ocean jointly.To study the effect of the wave-induced Stokes drift on the dynamics of the ocean mixed layer,a new three-dimensional(3D) numerical model is derived using the primitive basic equations and Eulerian wave averaging.The Princeton Ocean Model(POM),a 3D primitive equation ocean model is used with the upper wave-averaged basic equations.The global ocean circulation is simulated using the POM model,and the Stokes drift is evaluated based on the wave data generated by WAVEWATCH III.We compared simulations with and without the Stokes drift.The results show that the magnitude of the Stokes drift is comparable with the Eulerian mean current.Including the Stokes drift in the ocean model affects both the Eulerian current and the Lagranian drift and causes the vertical mixing coefficients to increase.展开更多
Deepwater deployment of offshore structures in different sea states was investigated. The whole deployment system was modeled as a lumped mass model, and discretization scheme for cable geometry and methodology for ca...Deepwater deployment of offshore structures in different sea states was investigated. The whole deployment system was modeled as a lumped mass model, and discretization scheme for cable geometry and methodology for calculating the internal and external force acting on deploying cable were presented. The deployment model suitable for the time-varying length of deploying cable was specified. The free-surface flow fields together with the ship motions were used to calculate dynamic tension in the deploying cable during deployment of the structure. The deployment of deep sea mining system which was a typical subsea working system was employed. Based on lumped mass analysis model and parameters of deep sea mining system, numerical simulations were performed, and dynamic load and dynamic amplification factor(DAF) with different cable parameters, deploying velocities and sea states were obtained. It is shown that cable parameters and amplitudes of ocean waves can significantly influence the dynamic load and DAF, and the time-varying natural period of deploying system is a dominant factor, while the effect of deploying velocity is not obvious.展开更多
The transshipment is an important issue in the current marine transportation. This paper constructed a mathematical programming model to elaborate the transshipment port selection for the shipping company. This model ...The transshipment is an important issue in the current marine transportation. This paper constructed a mathematical programming model to elaborate the transshipment port selection for the shipping company. This model is tested by the data collected from the ports of Hong Kong and Kaohsiung. The results show that this model can be used to explain the transshipment competition relationship between the ports of Hong Kong and Kaohsiung well. A sensitivity analysis was also executed. The sensitivity analysis results showed that both the port of Hong Kong and Kaohsiung should decrease the charges of port and increase the effi- ciency of loading and discharging. Based on the sensitivity analysis results, some interesting conclusions and helpful suggestions were obtained for the managers of the ports of Hong Kong and Kaohsiung to improve their port management.展开更多
A novel floating foundation to support the NREL offshore 5 MW wind turbine was designed conceptually by combining the characteristics of barge and Spar. The main focus was structural design and hydrodynamic modelling....A novel floating foundation to support the NREL offshore 5 MW wind turbine was designed conceptually by combining the characteristics of barge and Spar. The main focus was structural design and hydrodynamic modelling. Based on this novel floating foundation, the hydrodynamic performance was investigated in the frequency domain and time domain by using the wave analysis software Hydro D and Deep C from Det Norske Veritas. The frequency domain analysis was conducted to investigate the effects of the incident wave angle and water depth. The time-domain analysis was carried out to evaluate the response of the floating foundation under a selected operational condition. The hydrodynamic performances of this floating foundation with respect to time series and response spectra were also investigated in this study.展开更多
In this paper, the influential design thctors of wide-shallow composite bucket foundation for 3 MW off- shore wind turbine are systematically studied by numerical simulation. The results show that the bucket diameter ...In this paper, the influential design thctors of wide-shallow composite bucket foundation for 3 MW off- shore wind turbine are systematically studied by numerical simulation. The results show that the bucket diameter is larger than 27 m in generak and the range of 7--12 m is appropriate for cylinder height. In particular the bucket foun- dation with diameter of 30 m and cylinder height of 10 m is suitable for most soils. Under ultimate loads, the bucket diameter and elasticity modulus of soil have major effects on the deibrmability of bucket foundation, while the influ- ence of friction coefficient between the bucket and soil is relatively slight.展开更多
Based on the factors influencing location selection, this paper set up an evaluation system and got evaluation results of the related indexes in four main business centers in Shanghai with fuzzy comprehensive evaluati...Based on the factors influencing location selection, this paper set up an evaluation system and got evaluation results of the related indexes in four main business centers in Shanghai with fuzzy comprehensive evaluation method. In the mean time, this method can be applied in the evaluation of retail store location selection.展开更多
Marine emergencies especially oil spill may bring irreversible harm to the marine environment,and will cause immeasurable economic losses.In recent years,the demand for crude oil is increasing year by year in China wi...Marine emergencies especially oil spill may bring irreversible harm to the marine environment,and will cause immeasurable economic losses.In recent years,the demand for crude oil is increasing year by year in China with the high-speed economic development,leading to the high risk of marine oil spill.Therefore,it is necessary that promoting emergency response on marine oil spill in China and improving oil spill forecasting and early-warning techniques.This paper introduces the Marine Emergency Forecasting and Early-warning System(MEFES)developed by National Marine Data and Information Service(NMDIS).The system consists of one database,two modelling subsystems and a GIS platform.The database is the marine emergency database,and two subsystems include the marine environmental forecasting subsystem and the oil spill behaviour forecasting subsystem.MEFES has been applied in the emergency response of some major oil spill accidents occurred in recent years.The operational applications of the system can provide some theoretical basis and reference for marine oil spill emergency response.展开更多
This study was performed to compare storm surges/tide simulated by the regional and coastal storm surges/tide forecast system (RTSM (regional tide/storm surges model), CTSM (coastal tide/storm surges model)) usi...This study was performed to compare storm surges/tide simulated by the regional and coastal storm surges/tide forecast system (RTSM (regional tide/storm surges model), CTSM (coastal tide/storm surges model)) using two different inputs from weather models (RDAPS (Regional Data Assimilation and Prediction System) and KWRF (Korea Weather and Research Forecasting)) during two typhoons that occurred between 2007 and 2008. Both the RDAPS and KWRF are the operational weather forecasting system in KMA (Korea Meteorological Administration). The horizontal resolutions of RDAPS and KWRF are 30 and 10 km, respectively. The storm surges/tide was hind casted using sea wind and pressure fields of two Typhoons which was approaching Korean Peninsula. The CTSM using input from KWRF simulate very well the storm surges/tide pattern in the complex coastal areas. The result showed that the storm surges by the coastal storm surges/tide model with high resolution input was in well agreement with the observed sea level occurred by high tide and storm surges in the coastal areas.展开更多
Maritime transportation is one of the most important and extensive transportation modes in the world. Maritime transportation is the backbone of contemporary world trade and therefore special attention should be paid ...Maritime transportation is one of the most important and extensive transportation modes in the world. Maritime transportation is the backbone of contemporary world trade and therefore special attention should be paid to all subjects concerning this mode of transportation. It is also necessary to complement maritime transportation by other modes, such as rail and/or truck (road). This article deals with the problems of maritime transportation and provides the summary of recent developments, trends and statistics mainly on transatlantic maritime routes (Europe to US). Besides maritime transportation, this thesis also reviews the trends and statistics of rail and truck (road) transportation in US and Europe. The authors considers four Czech biggest cities (points of origin), five European ports, eight US ports and 10 biggest cities in US (points of destination). The adapted TCMMSP (transnational collaborative multi-mode shipping problem) is applied to this case study and it seeks to solve the transportation of a set of five shipments with unique O-D (origin-destination) pairs and volume. The end of the thesis summarizes the results and analyses the average costs, optimal set volume, optimal shipment routing and port analysis.展开更多
The mosaic structure of landscape of the central area of Shanghai Metropolis is studied by quantitative methods of landscape ecology based on Remote Sensing (RS) and Geographic Information System (GIS) in this paper. ...The mosaic structure of landscape of the central area of Shanghai Metropolis is studied by quantitative methods of landscape ecology based on Remote Sensing (RS) and Geographic Information System (GIS) in this paper. Firstly, landscapes are classified into eight categories: residential quarter, industrial quarter, road, other urban landscape, farmland, village and small town, on-building area, river and other water bodies (such as lake, etc.). Secondly, a GIS is designed and set up based on the remote sensing data and field investigation, and a digital map of landscape mosaic is made. Then the indexes of diversity, dominance, fragmentation and isolation, and fractal dimension of each type of landscape in different periods are calculated by using spatial analysis method of GIS. With reference to the calculated results, a series of relative issues are discussed.展开更多
The prediction of a ship's resistance especially the viscous wave-making resistance is an important issue in CFD applications. In this paper, the resistances of six ships from hull 1 to hull 6 with different hull for...The prediction of a ship's resistance especially the viscous wave-making resistance is an important issue in CFD applications. In this paper, the resistances of six ships from hull 1 to hull 6 with different hull forms advancing in still water are numerically studied using the solver naoe-FOAM-SJTU, which was developed based on the open source code package OpenFOAM. Different components of the resistances are computed and compared while considering two speed conditions (12 kn and 16 kn). The resistance of hull 3 is the smallest while that of hull 5 is the largest at the same speed. The results show hull 3 is a good reference for the design of similar ships, which can provide some valuable guidelines for hull form optimization.展开更多
文摘In this paper, ECOMSED (Estuarine Coastal Ocean Model with sediment transport) model is employed to simulate storm surge process caused by typhoon passing across East China Sea in nearly years. Capability of ECOMSED to simulate storm surge is validated by comparing model result with observed data. Sensitivity experiments are designed to study the influence of sea level rise on typhoon storm surge. Numerical experiment shows that influence of mean sea level rise on typhoon storm surge is non-uniform spatially and changes as typhoon process differs. Maybe fixed boundary method would weaken the influence of mean sea level rise on storm surge, and free boundary method is suggested for the succeeding study.
文摘Recently, as the oceanic activities are more and more frequently carried out, marine oil spill accidents bring to enormous harm to the economy and society in China, especially in the Offshore China. Marine oil spill is one kind of serious disasters which severely damages the marine environment. Aiming at the improvement of the emergency response system and response ability for the oil spill, the relative technologies on oil spill response are developed. This paper briefly introduces the developments and achievements of the oil spill numerical models, including the oil spill spreading model, the oil spill transport model, the oil particle model as well as the oil spill weathering model, which provide the theoretic criterions for the future work on the oil spill predicting and response.
基金supported by the National Natural Science Foundation of China(contract No.41006002,No.41206013 and No.41106004)Open Fund of State Key Laboratory of Satellite Ocean Environment Dynamics,Second Institute of Oceanography of SOA(contract No.SOED1305)+3 种基金Open Fund of the Key Laboratory of Ocean Circulation and Waves,Chinese Academy of Sciences(contract No.KLOCAW1302)the Public Science and Technology Research Funds Projects of Ocean(contract No.200905001,No.201005019,and No.201205018)the Natural Science Foundation of State Ocean Administration(contract No.2012202,No.2012223,and No.2012224)Open Fund of Key Laboratory of Physical Oceanography,MOE(contract of Song jun)
文摘Sea level seasonal variations in the east of China seas from 2004 to 2006 are simulated by the advanced ROMS model. The results show similar sea level spatial features with TOPEX/Poseidon observations, with annual ranges decreasing gradually from the sea coast to the Kuroshio region. By getting rid of wind stress in ROMS model, the simulated sea level results still show obvious seasonal variations. However, the phenomenon of sea level anomaly disappears in Min Zhe Current Coastwise (MZCF) and Su Bei current coastwise (SBCF), and the change of it from coastal area to ocean recedes. The seal level difference between Bohai, Yellow Sea (BYS) and East China Sea (ECS) becomes weaker in spring and autumn. The annual differences decrease obviously, and the gradual change of annual ranges from seacoast to the Kuroshio almost disappears. The annual ranges in BYS are nearly identical. The annual range ratio without the wind stress to with the wind stress increases gradually from the sea coast to Kuroshio region.
基金Supported by the National Basic Research Program of China (973 Program) (Nos. 2005CB422300,2007CB411804,2010CB428904)the National Natural Science Foundation of China (Nos. 40976001,40940025,41006002)+2 种基金Tianjin Municipal Science and Technology Commission Project (No. 09JCYBJC07400)the "111 Project" (No.B07036)the Program for New Century Excellent Talents in University (No. NECT-07-0781)
文摘For understanding more about the water exchange between the Kuroshio and the East China Sea,We studied the variability of the Kuroshio in the East China Sea(ECS) in the period of 1991 to 2008 using a three-dimensional circulation model,and calculated Kuroshio onshore volume transport in the ECS at the minimum of 0.48 Sv(1 Sv ;106 m3/s) in summer and the maximum of 1.69 Sv in winter.Based on the data of WOA05 and NCEP,The modeled result indicates that the Kuroshio transport east of Taiwan Island decreased since 2000.Lateral movements tended to be stronger at two ends of the Kuroshio in the ECS than that of the middle segment.In addition,we applied a spectral mixture model(SMM) to determine the exchange zone between the Kuroshio and the shelf water of the ECS.The result reveals a significantly negative correlation(coefficient of-0.78) between the area of exchange zone and the Kuroshio onshore transport at 200 m isobath in the ECS.This conclusion brings a new view for the water exchange between the Kuroshio and the East China Sea.Additional to annual and semi-annual signals,intra-seasonal signal of probably the Pacific origin may trigger the events of Kuroshio intrusion and exchange in the ECS.
基金Supported by the Shanghai Leading Academic Discipline Project Foundation under Grant No.T0602Supported by the Shanghai Education Commission Project Foundation under Grant No.05FZ10
文摘Quantified risk assessment(QRA) needs mathematicization of risk theory.However,attention has been paid almost exclusively to applications of assessment methods,which has led to neglect of research into fundamental theories,such as the relationships among risk,safety,danger,and so on.In order to solve this problem,as a first step,fundamental theoretical relationships about risk and risk management were analyzed for this paper in the light of mathematics,and then illustrated with some charts.Second,man-machine-environment-management(MMEM) theory was introduced into risk theory to analyze some properties of risk.On the basis of this,a three-dimensional model of risk management was established that includes:a goal dimension;a management dimension;an operation dimension.This goal management operation(GMO) model was explained and then emphasis was laid on the discussion of the risk flowchart(operation dimension),which lays the groundwork for further study of risk management and qualitative and quantitative assessment.Next,the relationship between Formal Safety Assessment(FSA) and Risk Management was researched.This revealed that the FSA method,which the international maritime organization(IMO) is actively spreading,comes from Risk Management theory.Finally,conclusion were made about how to apply this risk management method to concrete fields efficiently and conveniently,as well as areas where further research is required.
基金This work was supported by foundation of National Key Fundamental Research and Development Program (2002CB412406)
文摘The spatial pattern of urbanization in the Shanghai metropolitan area is quantified with GIS-based land use data set and gradient analysis of landscape metrics. A number of landscape metrics were computed along a 64 Ion long and 6 km wide west-east transect and another 66 km long and 6 km wide south-north transect. The results of transect analysis with class-level metrics showed that the spatial pattern of urbanization could be reliably quantified using landscape metrics with a gradient analysis approach, and the location of the urbanization center could be identified precisely and consistently with multiple indices of the landscape metrics used in this study. Different land use types exhibited distinctive, but not necessarily unique, spatial signatures that were dependent on specific landscape metrics. These results seemed to characterize the urban core of the Shanghai metropolitan area rather accurately and precisely.. Agriculture patches were abundant and less fragmented; the urban land use types were extensive, having many small patches and highly fragmented.
基金Under the auspices of National Natural Science Foundation of China (No. 40701177)
文摘This paper explores the potential to improve the impervious surface estimation accuracy using a multi-stage approach on the basis of vegetation-impervious surface-soil (V-I-S) model. In the first stage of Spectral Mixture Analysis (SMA) process, pixel purity index, a quantitative index for defining endmember quality, and a 3-dimensional endmember selection method were applied to refining endmembers. In the second stage, instead of obtaining impervious surface fraction by adding high and low albedo fractions directly, a linear regression model was built between impervious surface and high/low albedo using a random sampling method. The urban impervious surface distribution in the urban central area of Shanghai was predicted by the linear regression model. Estimation accuracy of spectral mixture analysis and impervious surface fraction were assessed using root mean square (RMS) and color aerial photography respectively. In comparison with three different research methods, this improved estimation method has a higher overall accuracy than traditional Linear Spectral Mixture Analysis (LSMA) method and the normalized SMA model both in root mean square error (RMSE) and standard error (SE). However, the model has a tendency to overestimate the impervious surface distribution.
基金National Basic Research Program of China or 973 Program (2009CB421505)Shanghai Key Agricultural Projects (Hu Nong Ke 2006-4-10)
文摘Hazard factors, hazard-bearling objects, disaster-developing environment, and disaster-preventing capability play key roles in the formation of Tropical Cyclone (TC) disasters. Of all of these, the most important is the intensity of hazard factors (risk sources). In this study, this intensity is uniformly defined by the probability of hazard factors; then a relationship is established between disaster risk intensity and hazard factors. The exceedance probability of various hazard factors, including frequency and timing, scope of wind and rain, and maximum wind and rain of impacting TC cases, are calculated using data from TCs that impacted Shanghai fi'om 1959-2006. The relationship between disaster situation and risk probability of hazard factors is analyzed, and the indices and model of TC disaster assessment are established based on the results. The process maximum wind speed and maximum daily precipitation are very important in TC-related disaster formation in Shanghai. The results of disaster indices coordinate with the results of the assessment model, and both can show the extent of probability of a TC disaster. Tests using TC data in 2007 and 2008 show that disasters caused by TC Krosa (0716) would be more serious than those by TC Wipha (0713), and that TC Fung Wong (0808) would have a weak impact. Real-life situations validate these results.
基金Supported by the National Natural Science Foundation of China(No.41376028)the Open Fund of the Shandong Province Key Laboratory of Ocean Engineering,Ocean University of China(No.201362045)
文摘The wave-forcing 'Coriolis-Stokes forcing' and 'Stokes-vortex force' induced by Stokes drift affect the upper ocean jointly.To study the effect of the wave-induced Stokes drift on the dynamics of the ocean mixed layer,a new three-dimensional(3D) numerical model is derived using the primitive basic equations and Eulerian wave averaging.The Princeton Ocean Model(POM),a 3D primitive equation ocean model is used with the upper wave-averaged basic equations.The global ocean circulation is simulated using the POM model,and the Stokes drift is evaluated based on the wave data generated by WAVEWATCH III.We compared simulations with and without the Stokes drift.The results show that the magnitude of the Stokes drift is comparable with the Eulerian mean current.Including the Stokes drift in the ocean model affects both the Eulerian current and the Lagranian drift and causes the vertical mixing coefficients to increase.
基金Project(51305463) supported by the National Natural Science Foundation of China
文摘Deepwater deployment of offshore structures in different sea states was investigated. The whole deployment system was modeled as a lumped mass model, and discretization scheme for cable geometry and methodology for calculating the internal and external force acting on deploying cable were presented. The deployment model suitable for the time-varying length of deploying cable was specified. The free-surface flow fields together with the ship motions were used to calculate dynamic tension in the deploying cable during deployment of the structure. The deployment of deep sea mining system which was a typical subsea working system was employed. Based on lumped mass analysis model and parameters of deep sea mining system, numerical simulations were performed, and dynamic load and dynamic amplification factor(DAF) with different cable parameters, deploying velocities and sea states were obtained. It is shown that cable parameters and amplitudes of ocean waves can significantly influence the dynamic load and DAF, and the time-varying natural period of deploying system is a dominant factor, while the effect of deploying velocity is not obvious.
文摘The transshipment is an important issue in the current marine transportation. This paper constructed a mathematical programming model to elaborate the transshipment port selection for the shipping company. This model is tested by the data collected from the ports of Hong Kong and Kaohsiung. The results show that this model can be used to explain the transshipment competition relationship between the ports of Hong Kong and Kaohsiung well. A sensitivity analysis was also executed. The sensitivity analysis results showed that both the port of Hong Kong and Kaohsiung should decrease the charges of port and increase the effi- ciency of loading and discharging. Based on the sensitivity analysis results, some interesting conclusions and helpful suggestions were obtained for the managers of the ports of Hong Kong and Kaohsiung to improve their port management.
基金Supported by the National Natural Science Foundation of China(No.51479134)the Science Fund for Creative Research Groups of the National Natural Science Foundation of China(No.51321065)the State Key Laboratory of Hydraulic Engineering Simulation and Safety
文摘A novel floating foundation to support the NREL offshore 5 MW wind turbine was designed conceptually by combining the characteristics of barge and Spar. The main focus was structural design and hydrodynamic modelling. Based on this novel floating foundation, the hydrodynamic performance was investigated in the frequency domain and time domain by using the wave analysis software Hydro D and Deep C from Det Norske Veritas. The frequency domain analysis was conducted to investigate the effects of the incident wave angle and water depth. The time-domain analysis was carried out to evaluate the response of the floating foundation under a selected operational condition. The hydrodynamic performances of this floating foundation with respect to time series and response spectra were also investigated in this study.
基金Supported by the National Natural Science Foundation of China(No.51379142)International Science and Technology Cooperation Program of China(No.2012DFA70490)Tianjin Municipal Natural Science Foundation(No.13JCYBJC19100 and No.13JCQNJC06900)
文摘In this paper, the influential design thctors of wide-shallow composite bucket foundation for 3 MW off- shore wind turbine are systematically studied by numerical simulation. The results show that the bucket diameter is larger than 27 m in generak and the range of 7--12 m is appropriate for cylinder height. In particular the bucket foun- dation with diameter of 30 m and cylinder height of 10 m is suitable for most soils. Under ultimate loads, the bucket diameter and elasticity modulus of soil have major effects on the deibrmability of bucket foundation, while the influ- ence of friction coefficient between the bucket and soil is relatively slight.
文摘Based on the factors influencing location selection, this paper set up an evaluation system and got evaluation results of the related indexes in four main business centers in Shanghai with fuzzy comprehensive evaluation method. In the mean time, this method can be applied in the evaluation of retail store location selection.
文摘Marine emergencies especially oil spill may bring irreversible harm to the marine environment,and will cause immeasurable economic losses.In recent years,the demand for crude oil is increasing year by year in China with the high-speed economic development,leading to the high risk of marine oil spill.Therefore,it is necessary that promoting emergency response on marine oil spill in China and improving oil spill forecasting and early-warning techniques.This paper introduces the Marine Emergency Forecasting and Early-warning System(MEFES)developed by National Marine Data and Information Service(NMDIS).The system consists of one database,two modelling subsystems and a GIS platform.The database is the marine emergency database,and two subsystems include the marine environmental forecasting subsystem and the oil spill behaviour forecasting subsystem.MEFES has been applied in the emergency response of some major oil spill accidents occurred in recent years.The operational applications of the system can provide some theoretical basis and reference for marine oil spill emergency response.
文摘This study was performed to compare storm surges/tide simulated by the regional and coastal storm surges/tide forecast system (RTSM (regional tide/storm surges model), CTSM (coastal tide/storm surges model)) using two different inputs from weather models (RDAPS (Regional Data Assimilation and Prediction System) and KWRF (Korea Weather and Research Forecasting)) during two typhoons that occurred between 2007 and 2008. Both the RDAPS and KWRF are the operational weather forecasting system in KMA (Korea Meteorological Administration). The horizontal resolutions of RDAPS and KWRF are 30 and 10 km, respectively. The storm surges/tide was hind casted using sea wind and pressure fields of two Typhoons which was approaching Korean Peninsula. The CTSM using input from KWRF simulate very well the storm surges/tide pattern in the complex coastal areas. The result showed that the storm surges by the coastal storm surges/tide model with high resolution input was in well agreement with the observed sea level occurred by high tide and storm surges in the coastal areas.
文摘Maritime transportation is one of the most important and extensive transportation modes in the world. Maritime transportation is the backbone of contemporary world trade and therefore special attention should be paid to all subjects concerning this mode of transportation. It is also necessary to complement maritime transportation by other modes, such as rail and/or truck (road). This article deals with the problems of maritime transportation and provides the summary of recent developments, trends and statistics mainly on transatlantic maritime routes (Europe to US). Besides maritime transportation, this thesis also reviews the trends and statistics of rail and truck (road) transportation in US and Europe. The authors considers four Czech biggest cities (points of origin), five European ports, eight US ports and 10 biggest cities in US (points of destination). The adapted TCMMSP (transnational collaborative multi-mode shipping problem) is applied to this case study and it seeks to solve the transportation of a set of five shipments with unique O-D (origin-destination) pairs and volume. The end of the thesis summarizes the results and analyses the average costs, optimal set volume, optimal shipment routing and port analysis.
文摘The mosaic structure of landscape of the central area of Shanghai Metropolis is studied by quantitative methods of landscape ecology based on Remote Sensing (RS) and Geographic Information System (GIS) in this paper. Firstly, landscapes are classified into eight categories: residential quarter, industrial quarter, road, other urban landscape, farmland, village and small town, on-building area, river and other water bodies (such as lake, etc.). Secondly, a GIS is designed and set up based on the remote sensing data and field investigation, and a digital map of landscape mosaic is made. Then the indexes of diversity, dominance, fragmentation and isolation, and fractal dimension of each type of landscape in different periods are calculated by using spatial analysis method of GIS. With reference to the calculated results, a series of relative issues are discussed.
基金Foundation item: Supported by the National Natural Science Foundation of China (Grant Nos.l1072154, 51379125), the National Key Basic Research Development Plan (973 Plan) Project of China (Grant No.2013CB036103), the High Technology of Marine Research Project of the Ministry of Industry and Information Technology of China and the Program for Professor of Special Appointment (Eastern Scholar) at Shanghai Institutions of Higher Learning (Grant No. 2013022).
文摘The prediction of a ship's resistance especially the viscous wave-making resistance is an important issue in CFD applications. In this paper, the resistances of six ships from hull 1 to hull 6 with different hull forms advancing in still water are numerically studied using the solver naoe-FOAM-SJTU, which was developed based on the open source code package OpenFOAM. Different components of the resistances are computed and compared while considering two speed conditions (12 kn and 16 kn). The resistance of hull 3 is the smallest while that of hull 5 is the largest at the same speed. The results show hull 3 is a good reference for the design of similar ships, which can provide some valuable guidelines for hull form optimization.