实现碳达峰碳中和涉及广泛而深刻的经济和社会系统性变革。基于构建的经济-能源-环境可计算一般均衡(computable general equilibrium,CGE)模型,在碳达峰后设置“凹型”、“凸型”和“直线型”3种实现碳中和的减排路径,分析了“双碳”...实现碳达峰碳中和涉及广泛而深刻的经济和社会系统性变革。基于构建的经济-能源-环境可计算一般均衡(computable general equilibrium,CGE)模型,在碳达峰后设置“凹型”、“凸型”和“直线型”3种实现碳中和的减排路径,分析了“双碳”目标下中国经济社会和产业发展的变化趋势。研究表明:第一,采用先慢后快的“凸型”碳减排方案时,2020年到2060年的累计GDP损失(相较基准情景而言)最小,约为2.5%,2060年中国碳价水平(边际减排成本)将超过2800元/t;第二,在碳中和目标约束下,2060年非化石能源消费在一次能源消费中的占比将达到80%以上,非化石能源发电占比将达到90%以上;第三,钢铁、有色金属、建材、化工等高耗能行业的减排对落实“双碳”目标具有重要作用,加快化石能源退出并提升清洁电力在能源消费中的占比是高耗能行业减排的重要方式。根据研究结论,建议设定全社会和各行业明确的减排目标,制定合理的碳中和减排路径时间表,明确逐步实现碳中和的阶段性目标;加快构建新型能源体系和新型电力系统,促进可再生能源大规模发展,实现清洁能源对化石能源的全面深度替代;制定重点行业实现碳中和的具体方案,推动能源与产业协同转型,加快提升电气化水平。展开更多
Crop water stress index(CWSI)is widely used for efficient irrigation management.Precise canopy temperature(T_(c))measurement is necessary to derive a reliable CWSI.The objective of this research was to investigate the...Crop water stress index(CWSI)is widely used for efficient irrigation management.Precise canopy temperature(T_(c))measurement is necessary to derive a reliable CWSI.The objective of this research was to investigate the influences of atmospheric conditions,settled height,view angle of infrared thermography,and investigating time of temperature measuring on the performance of the CWSI.Three irrigation treatments were used to create different soil water conditions during the 2020-2021 and 2021-2022 winter wheat-growing seasons.The CWSI was calculated using the CWSI-E(an empirical approach)and CWSI-T(a theoretical approach)based on the T_(c).Weather conditions were recorded continuously throughout the experimental period.The results showed that atmospheric conditions influenced the estimation of the CWSI;when the vapor pressure deficit(VPD)was>2000 Pa,the estimated CWSI was related to soil water conditions.The height of the installed infrared thermograph influenced the T_(c)values,and the differences among the T_(c)values measured at height of 3,5,and 10 m was smaller in the afternoon than in the morning.However,the lens of the thermometer facing south recorded a higher T_(c)than those facing east or north,especially at a low height,indicating that the direction of the thermometer had a significant influence on T_(c).There was a large variation in CWSI derived at different times of the day,and the midday measurements(12:00-15:00)were the most reliable for estimating CWSI.Negative linear relationships were found between the transpiration rate and CWSI-E(R^(2)of 0.3646-0.5725)and CWSI-T(R^(2)of 0.5407-0.7213).The relations between fraction of available soil water(FASW)with CWSI-T was higher than that with CWSI-E,indicating CWSI-T was more accurate for predicting crop water status.In addition,The R^(2)between CWSI-T and FASW at 14:00 was higher than that at other times,indicating that 14:00 was the optimal time for using the CWSI for crop water status monitoring.Relative higher yield of winter wheat was obtained with average seasonal values of CWSI-E and CWSI-T around 0.23 and 0.25-0.26,respectively.The CWSI-E values were more easily influenced by meteorological factors and the timing of the measurements,and using the theoretical approach to derive the CWSI was recommended for precise irrigation water management.展开更多
文摘实现碳达峰碳中和涉及广泛而深刻的经济和社会系统性变革。基于构建的经济-能源-环境可计算一般均衡(computable general equilibrium,CGE)模型,在碳达峰后设置“凹型”、“凸型”和“直线型”3种实现碳中和的减排路径,分析了“双碳”目标下中国经济社会和产业发展的变化趋势。研究表明:第一,采用先慢后快的“凸型”碳减排方案时,2020年到2060年的累计GDP损失(相较基准情景而言)最小,约为2.5%,2060年中国碳价水平(边际减排成本)将超过2800元/t;第二,在碳中和目标约束下,2060年非化石能源消费在一次能源消费中的占比将达到80%以上,非化石能源发电占比将达到90%以上;第三,钢铁、有色金属、建材、化工等高耗能行业的减排对落实“双碳”目标具有重要作用,加快化石能源退出并提升清洁电力在能源消费中的占比是高耗能行业减排的重要方式。根据研究结论,建议设定全社会和各行业明确的减排目标,制定合理的碳中和减排路径时间表,明确逐步实现碳中和的阶段性目标;加快构建新型能源体系和新型电力系统,促进可再生能源大规模发展,实现清洁能源对化石能源的全面深度替代;制定重点行业实现碳中和的具体方案,推动能源与产业协同转型,加快提升电气化水平。
基金supported by the Project of State Grid Hebei Electric Power Co.,Ltd.(SGHEYX00SCJS2100077).
文摘Crop water stress index(CWSI)is widely used for efficient irrigation management.Precise canopy temperature(T_(c))measurement is necessary to derive a reliable CWSI.The objective of this research was to investigate the influences of atmospheric conditions,settled height,view angle of infrared thermography,and investigating time of temperature measuring on the performance of the CWSI.Three irrigation treatments were used to create different soil water conditions during the 2020-2021 and 2021-2022 winter wheat-growing seasons.The CWSI was calculated using the CWSI-E(an empirical approach)and CWSI-T(a theoretical approach)based on the T_(c).Weather conditions were recorded continuously throughout the experimental period.The results showed that atmospheric conditions influenced the estimation of the CWSI;when the vapor pressure deficit(VPD)was>2000 Pa,the estimated CWSI was related to soil water conditions.The height of the installed infrared thermograph influenced the T_(c)values,and the differences among the T_(c)values measured at height of 3,5,and 10 m was smaller in the afternoon than in the morning.However,the lens of the thermometer facing south recorded a higher T_(c)than those facing east or north,especially at a low height,indicating that the direction of the thermometer had a significant influence on T_(c).There was a large variation in CWSI derived at different times of the day,and the midday measurements(12:00-15:00)were the most reliable for estimating CWSI.Negative linear relationships were found between the transpiration rate and CWSI-E(R^(2)of 0.3646-0.5725)and CWSI-T(R^(2)of 0.5407-0.7213).The relations between fraction of available soil water(FASW)with CWSI-T was higher than that with CWSI-E,indicating CWSI-T was more accurate for predicting crop water status.In addition,The R^(2)between CWSI-T and FASW at 14:00 was higher than that at other times,indicating that 14:00 was the optimal time for using the CWSI for crop water status monitoring.Relative higher yield of winter wheat was obtained with average seasonal values of CWSI-E and CWSI-T around 0.23 and 0.25-0.26,respectively.The CWSI-E values were more easily influenced by meteorological factors and the timing of the measurements,and using the theoretical approach to derive the CWSI was recommended for precise irrigation water management.
