Flood extremes due to sea level rise and extreme precipitation are expected to increase in frequency and intensity. However, despite the need for accurate climate change risk assessment, significant misconceptions in ...Flood extremes due to sea level rise and extreme precipitation are expected to increase in frequency and intensity. However, despite the need for accurate climate change risk assessment, significant misconceptions in key risk terms, including vulnerability and impact, could lead to risk miscalculations. These misconceptions around risk concepts derive from the lack of risk terms’ standardization and the gaps in an integrated and widely accepted methodology for assessing climate change risks. Risk assessment frameworks should follow the specialties of each element/sector it is applied on and the special features of each climate hazard. Also, risk assessment matrix should not follow specific design settings but it should better follow the needs of each study, so as to optimize the understanding of each risk. Through an extensive literature review, this is the first paper that identifies gaps, inconsistencies and misuses of climate risk concepts and suggests specific systemization and standardization of risk terms definitions. Finally, it develops a climate change risk assessment framework and matrix, focusing on sea level rise and extreme precipitation, which could be widely implemented in risk assessment of all elements at sea level rise and extreme precipitation risk.展开更多
The Thwaites Glacier in western Antarctica(Fig.1)keeps glaciologists and climate scientists awake at night.The 120 km-wide glacier loses about 45 billion tonnes of ice each year,account-ing for about 4%of global sea l...The Thwaites Glacier in western Antarctica(Fig.1)keeps glaciologists and climate scientists awake at night.The 120 km-wide glacier loses about 45 billion tonnes of ice each year,account-ing for about 4%of global sea level rise[1].If it melted completely,sea levels would climb 65 cm,and follow-on effects could lead to a 3 m increase[2].展开更多
In this study,a two-dimensional hydrodynamic and sediment transport model is established to quantify the influences of sea level rise on sediment transport in the Yangtze River Estuary(YRE).After validation,the model ...In this study,a two-dimensional hydrodynamic and sediment transport model is established to quantify the influences of sea level rise on sediment transport in the Yangtze River Estuary(YRE).After validation,the model was employed to investigate the sediment transport and seabed evolution under four different scenarios of sea level rise,specifically,0,0.5,1 and 1.5 m.The results reveal that there exists a‘transition point(TP)'of SSC in each main channel of YRE.Upstream of the transition point,the suspended sediment concentration(SSC)increases along with the rise in sea level,while downstream of the transition point,SSC decreases as sea level rises.Similarly,there are also transition points for topography evolution.The maximum scouring rate upstream of the transition points exceeds 4.32% for a 1.5 m rise in sea level,while the maximum deposition rate downstream of the transition points is 2.48%.The sediment fluxes from upstream to downstream in the branches of YRE are enhanced by the rise in sea level.The direction of sediment flux in the North Branch reverses downstream as sea level rises.The sediment flux from the North Channel towards downstream increases significantly,while there is no significant change in sediment flux for South Channel.Sediment deposition in the North Passage is also accelerated by sea level rise.In addition,the sediment flux from YRE to northern Jiangsu and Hangzhou Bay is also weakened by the rise in sea level.展开更多
As the global temperature continues to increase, the sea level continues to rise at a rapid rate that has never been seen before. This becomes an issue for many facets of life but one of the most impacted is the trans...As the global temperature continues to increase, the sea level continues to rise at a rapid rate that has never been seen before. This becomes an issue for many facets of life but one of the most impacted is the transportation infrastructure. Many people living in low elevation coastal areas can become trapped by flooding with no way in or out. With Delaware being a coastal state, this would affect a large portion of the population and will have detrimental effects over time if nothing is done to combat sea level rise. The issue with sea level rise in transportation is that once the roads become flooded, they become virtually unusable and detour routes would be needed. If all the roads in a coastal area were to be affected by sea level rise, the options for detours would become limited. This article looks at direct solutions to combat sea level rise and indirect solutions that would specifically help transportation infrastructure and evacuation routes in Delaware. There is not one solution that can fix every problem, so many solutions are laid out to see what is applicable to each affected area. Some solutions include defense structures that would be put close to the coast, raising the elevation of vulnerable roads throughout the state and including pumping stations to drain the water on the surface of the road. With an understanding of all these solutions around the world, the ultimate conclusion came in the form of a six-step plan that Delaware should take in order to best design against sea level rise in these coastal areas.展开更多
The development of vehicle integrated photovoltaics-powered electric vehicles (VIPV-EV) significantly reduces CO<sub>2</sub> emissions from the transport sector to realize a decarbonized society. Although ...The development of vehicle integrated photovoltaics-powered electric vehicles (VIPV-EV) significantly reduces CO<sub>2</sub> emissions from the transport sector to realize a decarbonized society. Although long-distance driving of VIPV-EV without electricity charging is expected in sunny regions, driving distance of VIPV-EV is affected by climate conditions such as solar irradiation and temperature rise of PV modules. In this paper, detailed analytical results for effects of climate conditions such as solar irradiation and temperature rise of PV modules upon driving distance of the VIPV-EV were presented by using test data for Toyota Prius and Nissan Van demonstration cars installed with high-efficiency InGaP/GaAs/InGaAs 3-junction solar cell modules with a module efficiency of more than 30%. The temperature rise of some PV modules studied in this study was shown to be expressed by some coefficients related to solar irradiation, wind speed and radiative cooling. The potential of VIPV-EV to be deployed in 10 major cities was also analyzed. Although sunshine cities such as Phoenix show the high reduction ratio of driving range with 17% due to temperature rise of VIPV modules, populous cities such as Tokyo show low reduction ratio of 9%. It was also shown in this paper that the difference between the driving distance of VIPV-EV driving in the morning and the afternoon is due to PV modules’ radiative cooling. In addition, the importance of heat dissipation of PV modules and the development of high-efficiency PV modules with better temperature coefficients was suggested in order to expand driving range of VIPV-EV. The effects of air-conditioner usage and partial shading in addition to the effects of temperature rise of VIPV modules were suggested as the other power losses of VIPV-EV.展开更多
Mangroves play a pivotal role in tropical and subtropical coastal ecosystem,yet they are highly vulnerable to the effects of climate change,particularly the accelerated global sea level rise(SLR)and stronger tropical ...Mangroves play a pivotal role in tropical and subtropical coastal ecosystem,yet they are highly vulnerable to the effects of climate change,particularly the accelerated global sea level rise(SLR)and stronger tropical cyclones(TCs).However,there is a lack of research addressing future simultaneous combined impacts of the slow-onset of SLR and rapid-onset of TCs on China's mangroves.In order to develop a comprehensive risk assessment method considering the superimposed effects of these two factors and analyze risk for mangroves in Dongzhaigang,Hainan Island,China,we used observational and climate model data to assess the risks to mangroves under low,intermediate,and very high greenhouse gas(GHG)emission scenarios(such as SSP1-2.6,SSP2-4.5,and SSP5-8.5)in 2030,2050,and 2100,and compiled a risk assessment scheme for mangroves in Dongzhaigang,China.The results showed that the combined risks from SLR and TCs will continue to rise;however,SLRs will increase in intensity,and TCs will decrease.The comprehensive risk of the Dongzhaigang mangroves posed by climate change will remain low under SSP1-2.6 and SSP2-4.5 scenarios by 2030,but it will increase substantially by 2100.While under SSP5-8.5 scenario,the risks to mangroves in Dongzhaigang are projected to increase considerably by 2050,and approximately 68.8%of mangroves will be at very high risk by 2100.The risk to the Dongzhaigang mangroves is not only influenced by the hazards but also closely linked to their exposure and vulnerability.We therefore propose climate resilience developmental responses for mangroves to address the effects of climate change.This study for the combined impact of TCs and SLR on mangroves in Dongzhaigang,China can enrich the method system of mangrove risk assessment and provide references for scientific management.展开更多
The Ba Lang sand beaches, located north of the Nha Trang Bay in Central Vietnam, are famous tourist attractions. However, they are experiencing shoreline and coastal erosion retreat, which is attributed to natural cau...The Ba Lang sand beaches, located north of the Nha Trang Bay in Central Vietnam, are famous tourist attractions. However, they are experiencing shoreline and coastal erosion retreat, which is attributed to natural causes (such as tropical depressions, storms, and monsoons) as well as human impacts (such as hydropower generation, sand dredging, and coastal works). According to the forecast of the Vietnam Ministry of Natural Resources and Environment, global climate change will cause the sea level to rise by 74 cm along the coast from the Dai Lanh Cape to the Ke Ga Cape (including the Ba Lang beaches) by the end of this century in the representative concentration pathway (RCP) 8.5 scenario. Sea level rise (SLR) due to global climate change is expected to aggravate the coastal erosion and shoreline retreat problems. In this study, coupled numerical models with the spectral wave module (MIKE 21 SW), hydrodynamic module (MIKE 21 HD), and sand transport module (MIKE 21 ST) in the MIKE 21 package were used to simulate waves, current fields, and sediment dynamics along the Ba Lang beaches considering the impact of SLR. These models were calibrated with the field data measured in December 2016. The results showed that SLR caused the wave height to increase and reduced the current speed and total sediment load in monsoon conditions. The increase in wave height was even intensified under the joint impact of SLR and extreme events.展开更多
A winding system is a time-varying system that considers complex nonlinear characteristics,and how to control the stability of the winding tension during the winding process is the primary problem that has hindered de...A winding system is a time-varying system that considers complex nonlinear characteristics,and how to control the stability of the winding tension during the winding process is the primary problem that has hindered development in this field in recent years.Many nonlinear factors affect the tension in the winding process,such as friction,structured uncertainties,unstructured uncertainties,and external interference.These terms severely restrict the tension tracking performance.Existing tension control strategies are mainly based on the composite control of the tension and speed loops,and previous studies involve complex decoupling operations.Owing to the large number of calculations required for this method,it is inconvenient for practical engineering applications.To simplify the tension generation mechanism and the influence of the nonlinear characteristics of the winding system,a simpler nonlinear dynamic model of the winding tension was established.An adaptive method was applied to update the feedback gain of the continuous robust integral of the sign of the error(RISE).Furthermore,an extended state observer was used to estimate modeling errors and external disturbances.The model disturbance term can be compensated for in the designed RISE controller.The asymptotic stability of the system was proven according to the Lyapunov stability theory.Finally,a comparative analysis of the proposed nonlinear controller and several other controllers was performed.The results indicated that the control of the winding tension was significantly enhanced.展开更多
惯容器是一种两端点加速度相关型控制元件,具有表观质量放大、耗能增效等特性,可更加高效、经济地进行结构振动控制,将惯容器表观质量增大的特性拓展到调谐减震装置中可实现轻量化振动控制。为研究高层结构上附加旋转惯质双调谐质量阻尼...惯容器是一种两端点加速度相关型控制元件,具有表观质量放大、耗能增效等特性,可更加高效、经济地进行结构振动控制,将惯容器表观质量增大的特性拓展到调谐减震装置中可实现轻量化振动控制。为研究高层结构上附加旋转惯质双调谐质量阻尼器(rotating inertia dual-tuned mass damper,RIDTMD)的轻量化振动控制效果,采用柔度法求逆的方法获得等效简化模型;通过结构模态分析、时程分析验证了等效模型的可靠性;建立附加RIDTMD多自由度结构的力学模型与运动方程;采取H_(2)优化和给定质量、阻尼参数的取值区间来确定RIDTMD的参数。在一个51层的框架核心筒结构上设计了RIDTMD,分析其在地震激励下的楼层位移、加速度和层间位移角等结构响应,频域与时程分析结果看,以调谐质量阻尼器(tuned mass damper,TMD)控制效果为目标的H_(2)优化设计可以使RIDTMD有着与TMD类似的振动控制效果,与无控结构相比,顶层峰值位移、均方根位移最大可分别降低18.0、32.9%,且RIDTMD的调谐质量比TMD减少30.0%。展开更多
[目的/意义]研究德国马歇尔基金会(German Marshall Fund of the United States,GMF)对华问题的认知,有助于分析研判美国对中国崛起的全球影响的舆论走向和战略决策,为中美关系、中欧关系等问题的研究提供启示。[方法/过程]本文通过对其...[目的/意义]研究德国马歇尔基金会(German Marshall Fund of the United States,GMF)对华问题的认知,有助于分析研判美国对中国崛起的全球影响的舆论走向和战略决策,为中美关系、中欧关系等问题的研究提供启示。[方法/过程]本文通过对其2019至2024年共894篇的研究成果分析,梳理主要作者与研究主题,基于GMF对“对华研究”的认知现状、话语偏见模式角度与对华话语偏见模式特征进行系统性分析。[结果/结论]近年来该基金会的研究成果存在明显的对华话语偏见,在主题设置中存在预设立场,客观上强化西方对“中国崛起”的焦虑情绪。基于该基金会的影响力,这些负面认知可能会对美国政府决策、他国政策及舆论产生负面影响。因此,必须持续做好与国外智库沟通工作,提升国内智库话语能力和建设水平,构建中国特色话语传播体系,在国际舆论场上发出中国声音,助力加快构建中国话语和中国叙事体系。展开更多
文摘Flood extremes due to sea level rise and extreme precipitation are expected to increase in frequency and intensity. However, despite the need for accurate climate change risk assessment, significant misconceptions in key risk terms, including vulnerability and impact, could lead to risk miscalculations. These misconceptions around risk concepts derive from the lack of risk terms’ standardization and the gaps in an integrated and widely accepted methodology for assessing climate change risks. Risk assessment frameworks should follow the specialties of each element/sector it is applied on and the special features of each climate hazard. Also, risk assessment matrix should not follow specific design settings but it should better follow the needs of each study, so as to optimize the understanding of each risk. Through an extensive literature review, this is the first paper that identifies gaps, inconsistencies and misuses of climate risk concepts and suggests specific systemization and standardization of risk terms definitions. Finally, it develops a climate change risk assessment framework and matrix, focusing on sea level rise and extreme precipitation, which could be widely implemented in risk assessment of all elements at sea level rise and extreme precipitation risk.
文摘The Thwaites Glacier in western Antarctica(Fig.1)keeps glaciologists and climate scientists awake at night.The 120 km-wide glacier loses about 45 billion tonnes of ice each year,account-ing for about 4%of global sea level rise[1].If it melted completely,sea levels would climb 65 cm,and follow-on effects could lead to a 3 m increase[2].
基金funded by the Key Laboratory of Ocean Space Resource Management Technology,MNR(No.KF-2021-106)the National Natural Science Foundation of China(No.42006143)+1 种基金the Natural Science Foundation of Zhejiang Province(No.LY22E090011)the Open Research Fund Program of Marine Ecological Restoration and Smart Ocean Engineering Research Center of Hebei Province(No.HBMESO2312)。
文摘In this study,a two-dimensional hydrodynamic and sediment transport model is established to quantify the influences of sea level rise on sediment transport in the Yangtze River Estuary(YRE).After validation,the model was employed to investigate the sediment transport and seabed evolution under four different scenarios of sea level rise,specifically,0,0.5,1 and 1.5 m.The results reveal that there exists a‘transition point(TP)'of SSC in each main channel of YRE.Upstream of the transition point,the suspended sediment concentration(SSC)increases along with the rise in sea level,while downstream of the transition point,SSC decreases as sea level rises.Similarly,there are also transition points for topography evolution.The maximum scouring rate upstream of the transition points exceeds 4.32% for a 1.5 m rise in sea level,while the maximum deposition rate downstream of the transition points is 2.48%.The sediment fluxes from upstream to downstream in the branches of YRE are enhanced by the rise in sea level.The direction of sediment flux in the North Branch reverses downstream as sea level rises.The sediment flux from the North Channel towards downstream increases significantly,while there is no significant change in sediment flux for South Channel.Sediment deposition in the North Passage is also accelerated by sea level rise.In addition,the sediment flux from YRE to northern Jiangsu and Hangzhou Bay is also weakened by the rise in sea level.
文摘As the global temperature continues to increase, the sea level continues to rise at a rapid rate that has never been seen before. This becomes an issue for many facets of life but one of the most impacted is the transportation infrastructure. Many people living in low elevation coastal areas can become trapped by flooding with no way in or out. With Delaware being a coastal state, this would affect a large portion of the population and will have detrimental effects over time if nothing is done to combat sea level rise. The issue with sea level rise in transportation is that once the roads become flooded, they become virtually unusable and detour routes would be needed. If all the roads in a coastal area were to be affected by sea level rise, the options for detours would become limited. This article looks at direct solutions to combat sea level rise and indirect solutions that would specifically help transportation infrastructure and evacuation routes in Delaware. There is not one solution that can fix every problem, so many solutions are laid out to see what is applicable to each affected area. Some solutions include defense structures that would be put close to the coast, raising the elevation of vulnerable roads throughout the state and including pumping stations to drain the water on the surface of the road. With an understanding of all these solutions around the world, the ultimate conclusion came in the form of a six-step plan that Delaware should take in order to best design against sea level rise in these coastal areas.
文摘The development of vehicle integrated photovoltaics-powered electric vehicles (VIPV-EV) significantly reduces CO<sub>2</sub> emissions from the transport sector to realize a decarbonized society. Although long-distance driving of VIPV-EV without electricity charging is expected in sunny regions, driving distance of VIPV-EV is affected by climate conditions such as solar irradiation and temperature rise of PV modules. In this paper, detailed analytical results for effects of climate conditions such as solar irradiation and temperature rise of PV modules upon driving distance of the VIPV-EV were presented by using test data for Toyota Prius and Nissan Van demonstration cars installed with high-efficiency InGaP/GaAs/InGaAs 3-junction solar cell modules with a module efficiency of more than 30%. The temperature rise of some PV modules studied in this study was shown to be expressed by some coefficients related to solar irradiation, wind speed and radiative cooling. The potential of VIPV-EV to be deployed in 10 major cities was also analyzed. Although sunshine cities such as Phoenix show the high reduction ratio of driving range with 17% due to temperature rise of VIPV modules, populous cities such as Tokyo show low reduction ratio of 9%. It was also shown in this paper that the difference between the driving distance of VIPV-EV driving in the morning and the afternoon is due to PV modules’ radiative cooling. In addition, the importance of heat dissipation of PV modules and the development of high-efficiency PV modules with better temperature coefficients was suggested in order to expand driving range of VIPV-EV. The effects of air-conditioner usage and partial shading in addition to the effects of temperature rise of VIPV modules were suggested as the other power losses of VIPV-EV.
基金Under the auspices of the National Key Research and Development Program of China (No.2017YFA0604902,2017YFA0604903,2017YFA0604901)。
文摘Mangroves play a pivotal role in tropical and subtropical coastal ecosystem,yet they are highly vulnerable to the effects of climate change,particularly the accelerated global sea level rise(SLR)and stronger tropical cyclones(TCs).However,there is a lack of research addressing future simultaneous combined impacts of the slow-onset of SLR and rapid-onset of TCs on China's mangroves.In order to develop a comprehensive risk assessment method considering the superimposed effects of these two factors and analyze risk for mangroves in Dongzhaigang,Hainan Island,China,we used observational and climate model data to assess the risks to mangroves under low,intermediate,and very high greenhouse gas(GHG)emission scenarios(such as SSP1-2.6,SSP2-4.5,and SSP5-8.5)in 2030,2050,and 2100,and compiled a risk assessment scheme for mangroves in Dongzhaigang,China.The results showed that the combined risks from SLR and TCs will continue to rise;however,SLRs will increase in intensity,and TCs will decrease.The comprehensive risk of the Dongzhaigang mangroves posed by climate change will remain low under SSP1-2.6 and SSP2-4.5 scenarios by 2030,but it will increase substantially by 2100.While under SSP5-8.5 scenario,the risks to mangroves in Dongzhaigang are projected to increase considerably by 2050,and approximately 68.8%of mangroves will be at very high risk by 2100.The risk to the Dongzhaigang mangroves is not only influenced by the hazards but also closely linked to their exposure and vulnerability.We therefore propose climate resilience developmental responses for mangroves to address the effects of climate change.This study for the combined impact of TCs and SLR on mangroves in Dongzhaigang,China can enrich the method system of mangrove risk assessment and provide references for scientific management.
文摘The Ba Lang sand beaches, located north of the Nha Trang Bay in Central Vietnam, are famous tourist attractions. However, they are experiencing shoreline and coastal erosion retreat, which is attributed to natural causes (such as tropical depressions, storms, and monsoons) as well as human impacts (such as hydropower generation, sand dredging, and coastal works). According to the forecast of the Vietnam Ministry of Natural Resources and Environment, global climate change will cause the sea level to rise by 74 cm along the coast from the Dai Lanh Cape to the Ke Ga Cape (including the Ba Lang beaches) by the end of this century in the representative concentration pathway (RCP) 8.5 scenario. Sea level rise (SLR) due to global climate change is expected to aggravate the coastal erosion and shoreline retreat problems. In this study, coupled numerical models with the spectral wave module (MIKE 21 SW), hydrodynamic module (MIKE 21 HD), and sand transport module (MIKE 21 ST) in the MIKE 21 package were used to simulate waves, current fields, and sediment dynamics along the Ba Lang beaches considering the impact of SLR. These models were calibrated with the field data measured in December 2016. The results showed that SLR caused the wave height to increase and reduced the current speed and total sediment load in monsoon conditions. The increase in wave height was even intensified under the joint impact of SLR and extreme events.
基金Supported by National Key R&D Program of China (Grant No.2018YFB2000702)National Natural Science Foundation of China (Grant No.52075262)Fok Ying-Tong Education Foundation of China (Grant No.171044)。
文摘A winding system is a time-varying system that considers complex nonlinear characteristics,and how to control the stability of the winding tension during the winding process is the primary problem that has hindered development in this field in recent years.Many nonlinear factors affect the tension in the winding process,such as friction,structured uncertainties,unstructured uncertainties,and external interference.These terms severely restrict the tension tracking performance.Existing tension control strategies are mainly based on the composite control of the tension and speed loops,and previous studies involve complex decoupling operations.Owing to the large number of calculations required for this method,it is inconvenient for practical engineering applications.To simplify the tension generation mechanism and the influence of the nonlinear characteristics of the winding system,a simpler nonlinear dynamic model of the winding tension was established.An adaptive method was applied to update the feedback gain of the continuous robust integral of the sign of the error(RISE).Furthermore,an extended state observer was used to estimate modeling errors and external disturbances.The model disturbance term can be compensated for in the designed RISE controller.The asymptotic stability of the system was proven according to the Lyapunov stability theory.Finally,a comparative analysis of the proposed nonlinear controller and several other controllers was performed.The results indicated that the control of the winding tension was significantly enhanced.
文摘惯容器是一种两端点加速度相关型控制元件,具有表观质量放大、耗能增效等特性,可更加高效、经济地进行结构振动控制,将惯容器表观质量增大的特性拓展到调谐减震装置中可实现轻量化振动控制。为研究高层结构上附加旋转惯质双调谐质量阻尼器(rotating inertia dual-tuned mass damper,RIDTMD)的轻量化振动控制效果,采用柔度法求逆的方法获得等效简化模型;通过结构模态分析、时程分析验证了等效模型的可靠性;建立附加RIDTMD多自由度结构的力学模型与运动方程;采取H_(2)优化和给定质量、阻尼参数的取值区间来确定RIDTMD的参数。在一个51层的框架核心筒结构上设计了RIDTMD,分析其在地震激励下的楼层位移、加速度和层间位移角等结构响应,频域与时程分析结果看,以调谐质量阻尼器(tuned mass damper,TMD)控制效果为目标的H_(2)优化设计可以使RIDTMD有着与TMD类似的振动控制效果,与无控结构相比,顶层峰值位移、均方根位移最大可分别降低18.0、32.9%,且RIDTMD的调谐质量比TMD减少30.0%。
文摘[目的/意义]研究德国马歇尔基金会(German Marshall Fund of the United States,GMF)对华问题的认知,有助于分析研判美国对中国崛起的全球影响的舆论走向和战略决策,为中美关系、中欧关系等问题的研究提供启示。[方法/过程]本文通过对其2019至2024年共894篇的研究成果分析,梳理主要作者与研究主题,基于GMF对“对华研究”的认知现状、话语偏见模式角度与对华话语偏见模式特征进行系统性分析。[结果/结论]近年来该基金会的研究成果存在明显的对华话语偏见,在主题设置中存在预设立场,客观上强化西方对“中国崛起”的焦虑情绪。基于该基金会的影响力,这些负面认知可能会对美国政府决策、他国政策及舆论产生负面影响。因此,必须持续做好与国外智库沟通工作,提升国内智库话语能力和建设水平,构建中国特色话语传播体系,在国际舆论场上发出中国声音,助力加快构建中国话语和中国叙事体系。
