The study discusses accuracy evaluation methods for offshore wind energy resources by using scatterometer SeaWinds-derived wind speed and Weibull parameters. The purpose of this study is to evaluate accuracies of SeaW...The study discusses accuracy evaluation methods for offshore wind energy resources by using scatterometer SeaWinds-derived wind speed and Weibull parameters. The purpose of this study is to evaluate accuracies of SeaWinds-derived Weibull mean wind speed and energy density by considering uncertainties inherent in SeaWinds wind speed estimates. In this study, 1159 SeaWinds-derived wind speeds covering the KEO buoy are used for estimating two Weibull parameters, scale and shape. On the other hand, observed wind speeds from 2004 to 2008 at the KEO buoy are used for simulating three kinds of wind speeds in order to quantify some uncertainties inherent in SeaWinds-derived wind speeds. It is found that uncertainties associated with wind speed estimates （operational wind speed range, sampling time） show small differences in scale, shape and Weibull mean wind speed except energy density among the simulated datasets. Furthermore, the upper and lower bounds of 90% confidence interval corresponding to SeaWinds number of observations indicate 4-2.5% error of Weibull mean wind speed and 4-6.8% error of energy density, respectively.展开更多
Zhangjiakou region is situated in an agro-pastoral ecotone with a fragile ecosystem. While it has limited surface water resources available and serious groundwater over-exploitation, the city is located in the water c...Zhangjiakou region is situated in an agro-pastoral ecotone with a fragile ecosystem. While it has limited surface water resources available and serious groundwater over-exploitation, the city is located in the water conservation zone for the Beijing-Tianjin-Hebei coordinated development area, so its water security is crucial for the entire Beijing-Tianjin-Hebei region. Therefore, it is of vital significance to determine the zoning management of water resources and decision-making according to the magnitude of water resource security risks. This study built an indicator system for water security risk assessment in line with the principles of scientific validity, comparability, operability, and data availability, and this system gives weights to these indicators using the AHP approach. County-level multi-source data for the study area, based on water resource zones, were collected by using mathematical statistics and 3 S technology. With normalized data and a weighting method the water security risks were calculated. The results showed large spatial variations of water security risks in Zhangjiakou on the scales of geomorphic and administrative units as well as river basins. High-risk areas are extensive in the Bashang Plateau, and extremely high risk values are found in the Baxia areas. On the watershed scale, high-risk areas are mainly distributed in the inland river basins and the Yongding River basin. The risk values of the Luanhe River, Chaobai River and Daqing River basins in the Zhangjiakou region tend to decrease from north to south. For the northern and western areas of the Bashang Plateau, the factor of "vulnerability of the disaster-prone environment" contributes the most to the water security risk level. Agricultural water use constrains industrial and ecological water use, but in the context of inadequate water resource endowments, the urban population concentration and industrial development are the main causes of water shortages and water pollution so they contribute more to water security risks. This study of the spatial variation of water security risks in Zhangjiakou can provide an important scientific reference for zone-based management and decision-making for reducing the water security risks in the farming-pastoral ecotone.展开更多
文摘The study discusses accuracy evaluation methods for offshore wind energy resources by using scatterometer SeaWinds-derived wind speed and Weibull parameters. The purpose of this study is to evaluate accuracies of SeaWinds-derived Weibull mean wind speed and energy density by considering uncertainties inherent in SeaWinds wind speed estimates. In this study, 1159 SeaWinds-derived wind speeds covering the KEO buoy are used for estimating two Weibull parameters, scale and shape. On the other hand, observed wind speeds from 2004 to 2008 at the KEO buoy are used for simulating three kinds of wind speeds in order to quantify some uncertainties inherent in SeaWinds-derived wind speeds. It is found that uncertainties associated with wind speed estimates （operational wind speed range, sampling time） show small differences in scale, shape and Weibull mean wind speed except energy density among the simulated datasets. Furthermore, the upper and lower bounds of 90% confidence interval corresponding to SeaWinds number of observations indicate 4-2.5% error of Weibull mean wind speed and 4-6.8% error of energy density, respectively.
基金The National Major Science and Technology Program for Water Pollution Control and Treatment (2017ZX07101001)Guizhou Normal University Doctoral Funds (GZNUD20178, GZNUD20179)Science and Technology Program of Guizhou Province (20191218, 20191222, 20201Z031)。
文摘Zhangjiakou region is situated in an agro-pastoral ecotone with a fragile ecosystem. While it has limited surface water resources available and serious groundwater over-exploitation, the city is located in the water conservation zone for the Beijing-Tianjin-Hebei coordinated development area, so its water security is crucial for the entire Beijing-Tianjin-Hebei region. Therefore, it is of vital significance to determine the zoning management of water resources and decision-making according to the magnitude of water resource security risks. This study built an indicator system for water security risk assessment in line with the principles of scientific validity, comparability, operability, and data availability, and this system gives weights to these indicators using the AHP approach. County-level multi-source data for the study area, based on water resource zones, were collected by using mathematical statistics and 3 S technology. With normalized data and a weighting method the water security risks were calculated. The results showed large spatial variations of water security risks in Zhangjiakou on the scales of geomorphic and administrative units as well as river basins. High-risk areas are extensive in the Bashang Plateau, and extremely high risk values are found in the Baxia areas. On the watershed scale, high-risk areas are mainly distributed in the inland river basins and the Yongding River basin. The risk values of the Luanhe River, Chaobai River and Daqing River basins in the Zhangjiakou region tend to decrease from north to south. For the northern and western areas of the Bashang Plateau, the factor of "vulnerability of the disaster-prone environment" contributes the most to the water security risk level. Agricultural water use constrains industrial and ecological water use, but in the context of inadequate water resource endowments, the urban population concentration and industrial development are the main causes of water shortages and water pollution so they contribute more to water security risks. This study of the spatial variation of water security risks in Zhangjiakou can provide an important scientific reference for zone-based management and decision-making for reducing the water security risks in the farming-pastoral ecotone.
