To manage water resources effectively, a multiscale assessment of the vulnerability of water resources on the basis of political boundaries and watersheds is necessary. This study addressed issues on the vulnerability...To manage water resources effectively, a multiscale assessment of the vulnerability of water resources on the basis of political boundaries and watersheds is necessary. This study addressed issues on the vulnerability of water resources and provided a multiscale comparison of spatial heterogeneity under a climate change background. Using improved quantitative evaluation methods of vulnerabil- ity, the Theil index and the Shannon-Weaver index, we evaluated the vulnerability of water resources and its spatial heterogeneity in the Haihe River Basin in four scales, namely, second-class water resource regions （Class II WRRs）, third-class water resource regions （Class III WRRs）, Province-Class II WRRs, and Province-Class III WRRs. Results show that vulnerability enhances from the north to south in the different scales, and shows obvious spatial heterogeneity instead of moving toward convergence in multiscale assessment results. Among the Class II WRRs, the Tuhai-Majia River is the most vulnerable area, and the vulnerability of the Luanhe River is lower than that of the north of the Haihe River Basin, which in turn is lower than that of the south of the Haihe River Basin. In the scales of Class III WRRs and Province-Class III WRRs, the vulnerability shows obvious spatial heterogeneity and diversity measured by the Theil index and the Shannon-Weaver index. Multiscale vulnerability assessment results based on political boundaries and the watersheds of the Haihe River Basin innovatively provided in this paper are important and useful to characterize the real spatial pattern of the vulnerability of water resources and improve water resource management.展开更多
Future temperature distributions of the marginal Chinese seas are studied by dynamic downscaling of global CCSM3 IPCC_AR4 scenario runs. Different forcing fields from 2080-2099 Special Report on Emissions Scenarios （...Future temperature distributions of the marginal Chinese seas are studied by dynamic downscaling of global CCSM3 IPCC_AR4 scenario runs. Different forcing fields from 2080-2099 Special Report on Emissions Scenarios （SRES） B1, A1, and A2 to 1980-1999 20C3M are averaged and superimposed on CORE2 and SODA2.2.4 data to force high-resolution regional future simulations using the Regional Ocean Modeling System （ROMS）. Volume transport increments in downscaling simulation support the CCSM3 result that with a weakening subtropical gyre circulation, the Kuroshio Current in the East China Sea （ECS） is possibly strengthened under the global wanning scheme. This mostly relates to local wind change, whereby the summer monsoon is strengthened and winter monsoon weakened. Future temperature fluxes and their seasonal variations are larger than in the CCSM3 result. Downscaling 100 years＇ temperature increments are comparable to the CCSM3, with a minimum in B1 scenario of 1.2-2.0~C and a maximum in A2 scenario of 2.5-4.5~C. More detailed temperature distributions are shown in the downscaling simulation. Larger increments are in the Bohai Sea and middle Yellow Sea, and smaller increments near the southeast coast of China, west coast of Korea, and southern ECS. There is a reduction of advective heat north of Taiwan Island and west of Tsushima in summer, and along the southern part of the Yellow Sea warm current in winter. There is enhancement of advective heat in the northern Yellow Sea in winter, related to the delicate temperature increment distribution. At 50 meter depth, the Yellow Sea cold water mass is destroyed. Our simulations suggest that in the formation season of the cold water mass, regional temperature is higher in the future and the water remains at the bottom until next summer. In summer, the mixed layer is deeper, making it much easier for the strengthened surface heat flux to penetrate to the bottom of this water.展开更多
Climatic extremes such as drought have becoming a severe climate-related problem in many regions all over the world that can induce anomalies in vegetation condition. Growth and CO2 uptake by plants are constrained to...Climatic extremes such as drought have becoming a severe climate-related problem in many regions all over the world that can induce anomalies in vegetation condition. Growth and CO2 uptake by plants are constrained to a large extent by drought.Therefore, it is important to understand the spatial and temporal responses of vegetation to drought across the various land cover types and different regions. Leaf area index(LAI) derived from Global Land Surface Satellite(GLASS) data was used to evaluate the response of vegetation to drought occurrence across Yunnan Province, China(2001-2010). The meteorological drought was assessed based on Standardized Precipitation Index(SPI)values. Pearson's correlation coefficients between LAI and SPI were examined across several timescales within six sub-regions of the Yunnan. Further, the drought-prone area was identified based on LAI anomaly values. Lag and cumulative effects of lack of precipitation on vegetation were evident, with significant correlations found using 3-, 6-, 9-and 12-month timescale. We found 9-month timescale has higher correlations compared to another timescale.Approximately 29.4% of Yunnan's area was classified as drought-prone area, based on the LAI anomaly values. Most of this drought-prone area was distributed in the mountainous region of Yunnan.From the research, it is evident that GLASS LAI can be effectively used as an indicator for assessing drought conditions and it provide valuable information for drought risk defense and preparedness.展开更多
This study focused on the quantitative evaluation of the impact of the spatio-temporal scale used in data collection and grouping on the standardization of CPUE(catch per unit effort).We used the Chinese squid-jigging...This study focused on the quantitative evaluation of the impact of the spatio-temporal scale used in data collection and grouping on the standardization of CPUE(catch per unit effort).We used the Chinese squid-jigging fishery in the northwestern Pacific Ocean as an example to evaluate 24 scenarios at different spatio-temporal scales,with a combination of four levels of temporal scale(weekly,biweekly,monthly,and bimonthly)and six levels of spatial scale(longitude×latitude:0.5°×0.5°,0.5°×1°,0.5°×2°,1°×0.5°,1°×1°,and 1°×2°).We applied generalized additive models and generalized linear models to analyze the24 scenarios for CPUE standardization,and then the differences in the standardized CPUE among these scenarios were quantified.This study shows that combinations of different spatial and temporal scales could have different impacts on the standardization of CPUE.However,at a fine temporal scale(weekly)different spatial scales yielded similar results for standardized CPUE.The choice of spatio-temporal scale used in data collection and analysis may create added uncertainty in fisheries stock assessment and management.To identify a cost-effective spatio-temporal scale for data collection,we recommend a similar study be undertaken to facilitate the design of effective monitoring programs.展开更多
The objective of this study is to develop a unique modeling approach for fast assessment of massive soil erosion by water at a regional scale in the Loess Plateau, China. This approach relies on an understanding of bo...The objective of this study is to develop a unique modeling approach for fast assessment of massive soil erosion by water at a regional scale in the Loess Plateau, China. This approach relies on an understanding of both regional patterns of soil loss and its impact factors in the plateau area. Based on the regional characteristics of precipitation, vegetation and land form, and with the use of Landsat TM and ground investigation data, the entire Loess Plateau was first divided into 3 380 Fundamental Assessment Units （FAUs） to adapt to this regional modeling and fast assessment. A set of easily available parameters reflecting relevant water erosion factors at a regional scale was then developed, in which dynamic and static factors were discriminated. Arclnfo GIS was used to integrate all essential data into a central database. A resulting mathematical model was established to link the sediment yields and the selected variables on the basis of FAUs through overlay in GIS and multiple regression analyses. The sensitivity analyses and validation results show that this approach works effectively in assessing large area soil erosion, and also helps to understand the regional associations of erosion and its impact factors, and thus might significantly contribute to planning and policymaking for a large area erosion control in the Loess Plateau.展开更多
This paper systematically investigates telecommunication industry's "internet-and-digitization" development situation. Based on existing literature and the unique characteristics of telecommunication ind...This paper systematically investigates telecommunication industry's "internet-and-digitization" development situation. Based on existing literature and the unique characteristics of telecommunication industry, we build a comprehensive model to depict the level of "internet-and-digitization" development by five key dimensions: market size, informational investment, technological innovation, internet application, and internet penetration. We propose that this five-dimensional model can capture the key components of "internet-and-digitization" development in this digital era. By using Beijing's telecommunication data, we empirically test our conceptual model and explore the current development level of telecommunication industry's "internet-and-digitization" progress. Results show that Beijing's telecommunication industry has great potential in expanding online market size as well as activating technological innovation. We also suggest that bigger telecommunication firms should pay more attention to "internet-and-digitization" development, especially on internet application and penetration dimensions. Finally, theoretical contributions, managerial implications and future research directions are also discussed.展开更多
Fatigue cracks and fatigue damage have been important issues for ships and offshore structures for a long time.However,in the last decade,with the introduction of higher tensile steel in hull structures and increasing...Fatigue cracks and fatigue damage have been important issues for ships and offshore structures for a long time.However,in the last decade,with the introduction of higher tensile steel in hull structures and increasingly large ship dimensions,the greater attention should be paid to fatigue problems.Most research focuses on how to more easily access the fatigue strength of ships.Also,the major classification societies have already released their fatigue assessment notes.However,due to the complexity of factors influencing fatigue performances,such as wave load and pressure from cargo,the combination of different stress components,stress on concentration of local structure details,means stress,and the corrosive environments,there are different specifications with varying classification societies,leading to the different results from different fatigue assessment methods.This paper established the Det Norske Veritas（DNV） classification notes ＂fatigue assessment of ship structures＂ that explains the process of fatigue assessment and simplified methods.Finally,a fatigue analysis was performed by use data of a real ship and the reliability of the result was assessed.展开更多
基金Under the auspices of National Natural Science Foundation of China(No.51279140,51249010)National Basic Research Program of China(No.2010CB428406)
文摘To manage water resources effectively, a multiscale assessment of the vulnerability of water resources on the basis of political boundaries and watersheds is necessary. This study addressed issues on the vulnerability of water resources and provided a multiscale comparison of spatial heterogeneity under a climate change background. Using improved quantitative evaluation methods of vulnerabil- ity, the Theil index and the Shannon-Weaver index, we evaluated the vulnerability of water resources and its spatial heterogeneity in the Haihe River Basin in four scales, namely, second-class water resource regions （Class II WRRs）, third-class water resource regions （Class III WRRs）, Province-Class II WRRs, and Province-Class III WRRs. Results show that vulnerability enhances from the north to south in the different scales, and shows obvious spatial heterogeneity instead of moving toward convergence in multiscale assessment results. Among the Class II WRRs, the Tuhai-Majia River is the most vulnerable area, and the vulnerability of the Luanhe River is lower than that of the north of the Haihe River Basin, which in turn is lower than that of the south of the Haihe River Basin. In the scales of Class III WRRs and Province-Class III WRRs, the vulnerability shows obvious spatial heterogeneity and diversity measured by the Theil index and the Shannon-Weaver index. Multiscale vulnerability assessment results based on political boundaries and the watersheds of the Haihe River Basin innovatively provided in this paper are important and useful to characterize the real spatial pattern of the vulnerability of water resources and improve water resource management.
基金Supported by the National Basic Research Program of China(973 Program)(No.2012CB417401)the Knowledge Innovation Program of Chinese Academy of Sciences(No.KZCX2-EW-201)the Open Fund of Key Laboratory of Data Analysis and Applications,FIO(No.LDAA2011-03)
文摘Future temperature distributions of the marginal Chinese seas are studied by dynamic downscaling of global CCSM3 IPCC_AR4 scenario runs. Different forcing fields from 2080-2099 Special Report on Emissions Scenarios （SRES） B1, A1, and A2 to 1980-1999 20C3M are averaged and superimposed on CORE2 and SODA2.2.4 data to force high-resolution regional future simulations using the Regional Ocean Modeling System （ROMS）. Volume transport increments in downscaling simulation support the CCSM3 result that with a weakening subtropical gyre circulation, the Kuroshio Current in the East China Sea （ECS） is possibly strengthened under the global wanning scheme. This mostly relates to local wind change, whereby the summer monsoon is strengthened and winter monsoon weakened. Future temperature fluxes and their seasonal variations are larger than in the CCSM3 result. Downscaling 100 years＇ temperature increments are comparable to the CCSM3, with a minimum in B1 scenario of 1.2-2.0~C and a maximum in A2 scenario of 2.5-4.5~C. More detailed temperature distributions are shown in the downscaling simulation. Larger increments are in the Bohai Sea and middle Yellow Sea, and smaller increments near the southeast coast of China, west coast of Korea, and southern ECS. There is a reduction of advective heat north of Taiwan Island and west of Tsushima in summer, and along the southern part of the Yellow Sea warm current in winter. There is enhancement of advective heat in the northern Yellow Sea in winter, related to the delicate temperature increment distribution. At 50 meter depth, the Yellow Sea cold water mass is destroyed. Our simulations suggest that in the formation season of the cold water mass, regional temperature is higher in the future and the water remains at the bottom until next summer. In summer, the mixed layer is deeper, making it much easier for the strengthened surface heat flux to penetrate to the bottom of this water.
基金a part of the Project on "Building Effective Water Governance in the Asian Highlands" supported by Canada’s International Development Research Centre (IDRC)National Science Foundation of China, Grant No. 31270524the CGIAR research programs on ‘Climate change adaptation and mitigation’ (CRP6.4)
文摘Climatic extremes such as drought have becoming a severe climate-related problem in many regions all over the world that can induce anomalies in vegetation condition. Growth and CO2 uptake by plants are constrained to a large extent by drought.Therefore, it is important to understand the spatial and temporal responses of vegetation to drought across the various land cover types and different regions. Leaf area index(LAI) derived from Global Land Surface Satellite(GLASS) data was used to evaluate the response of vegetation to drought occurrence across Yunnan Province, China(2001-2010). The meteorological drought was assessed based on Standardized Precipitation Index(SPI)values. Pearson's correlation coefficients between LAI and SPI were examined across several timescales within six sub-regions of the Yunnan. Further, the drought-prone area was identified based on LAI anomaly values. Lag and cumulative effects of lack of precipitation on vegetation were evident, with significant correlations found using 3-, 6-, 9-and 12-month timescale. We found 9-month timescale has higher correlations compared to another timescale.Approximately 29.4% of Yunnan's area was classified as drought-prone area, based on the LAI anomaly values. Most of this drought-prone area was distributed in the mountainous region of Yunnan.From the research, it is evident that GLASS LAI can be effectively used as an indicator for assessing drought conditions and it provide valuable information for drought risk defense and preparedness.
基金Supported by Shanghai Universities First-class Disciplines Project,Discipline name:Fisheries(A),the National Natural Science Foundation of China(No.NSFC41276156)the National High Technology Research and Development Program of China(863 Program)(No.2012AA092303)+1 种基金the Shanghai Science and Technology Innovation Program(No.12231203900)CHEN Yong’s involvement was supported by the Shanghai Ocean University
文摘This study focused on the quantitative evaluation of the impact of the spatio-temporal scale used in data collection and grouping on the standardization of CPUE(catch per unit effort).We used the Chinese squid-jigging fishery in the northwestern Pacific Ocean as an example to evaluate 24 scenarios at different spatio-temporal scales,with a combination of four levels of temporal scale(weekly,biweekly,monthly,and bimonthly)and six levels of spatial scale(longitude×latitude:0.5°×0.5°,0.5°×1°,0.5°×2°,1°×0.5°,1°×1°,and 1°×2°).We applied generalized additive models and generalized linear models to analyze the24 scenarios for CPUE standardization,and then the differences in the standardized CPUE among these scenarios were quantified.This study shows that combinations of different spatial and temporal scales could have different impacts on the standardization of CPUE.However,at a fine temporal scale(weekly)different spatial scales yielded similar results for standardized CPUE.The choice of spatio-temporal scale used in data collection and analysis may create added uncertainty in fisheries stock assessment and management.To identify a cost-effective spatio-temporal scale for data collection,we recommend a similar study be undertaken to facilitate the design of effective monitoring programs.
基金Under the auspices of Northeast Normal University Sci-tech Innovation Incubation Program(No.NENU-STC08017)European Commission FP7 Project―PRACTICE(No.ENVI-2008-226818)
文摘The objective of this study is to develop a unique modeling approach for fast assessment of massive soil erosion by water at a regional scale in the Loess Plateau, China. This approach relies on an understanding of both regional patterns of soil loss and its impact factors in the plateau area. Based on the regional characteristics of precipitation, vegetation and land form, and with the use of Landsat TM and ground investigation data, the entire Loess Plateau was first divided into 3 380 Fundamental Assessment Units （FAUs） to adapt to this regional modeling and fast assessment. A set of easily available parameters reflecting relevant water erosion factors at a regional scale was then developed, in which dynamic and static factors were discriminated. Arclnfo GIS was used to integrate all essential data into a central database. A resulting mathematical model was established to link the sediment yields and the selected variables on the basis of FAUs through overlay in GIS and multiple regression analyses. The sensitivity analyses and validation results show that this approach works effectively in assessing large area soil erosion, and also helps to understand the regional associations of erosion and its impact factors, and thus might significantly contribute to planning and policymaking for a large area erosion control in the Loess Plateau.
基金supportive funding by The National Social Science Fund of China (No. 16BGL163)
文摘This paper systematically investigates telecommunication industry's "internet-and-digitization" development situation. Based on existing literature and the unique characteristics of telecommunication industry, we build a comprehensive model to depict the level of "internet-and-digitization" development by five key dimensions: market size, informational investment, technological innovation, internet application, and internet penetration. We propose that this five-dimensional model can capture the key components of "internet-and-digitization" development in this digital era. By using Beijing's telecommunication data, we empirically test our conceptual model and explore the current development level of telecommunication industry's "internet-and-digitization" progress. Results show that Beijing's telecommunication industry has great potential in expanding online market size as well as activating technological innovation. We also suggest that bigger telecommunication firms should pay more attention to "internet-and-digitization" development, especially on internet application and penetration dimensions. Finally, theoretical contributions, managerial implications and future research directions are also discussed.
文摘Fatigue cracks and fatigue damage have been important issues for ships and offshore structures for a long time.However,in the last decade,with the introduction of higher tensile steel in hull structures and increasingly large ship dimensions,the greater attention should be paid to fatigue problems.Most research focuses on how to more easily access the fatigue strength of ships.Also,the major classification societies have already released their fatigue assessment notes.However,due to the complexity of factors influencing fatigue performances,such as wave load and pressure from cargo,the combination of different stress components,stress on concentration of local structure details,means stress,and the corrosive environments,there are different specifications with varying classification societies,leading to the different results from different fatigue assessment methods.This paper established the Det Norske Veritas（DNV） classification notes ＂fatigue assessment of ship structures＂ that explains the process of fatigue assessment and simplified methods.Finally,a fatigue analysis was performed by use data of a real ship and the reliability of the result was assessed.
