为了体现次网格尺度能量升尺度转换过程中存在的不确定性,文中将随机动能补偿(Stochastic Kinetic Energy Backscatter,SKEB)方案应用于GRAPES(Global/Regional Assimilation and Prediction System)全球集合预报系统(GRAPES-GEPS),以...为了体现次网格尺度能量升尺度转换过程中存在的不确定性,文中将随机动能补偿(Stochastic Kinetic Energy Backscatter,SKEB)方案应用于GRAPES(Global/Regional Assimilation and Prediction System)全球集合预报系统(GRAPES-GEPS),以更好地表征模式误差并且增大集合离散度。使用的SKEB方案基于具有一定时、空相关特征的随机型以及由数值扩散导致的局地动能耗散率来构造随机流函数强迫。并根据流函数与水平风速旋转分量的关系,将SKEB方案中的流函数强迫转化为适用于GRAPES全球模式的水平风速扰动。结果表明,SKEB方案的使用一方面能够提高GRAPES对大气动能谱的模拟能力;另一方面能够改善GRAPES-GEPS的集合离散度与集合平均误差的关系,增加了集合离散度,并在一定程度上减小了集合平均误差,尤其是在热带地区这种改进更为显著。而且该方案使得热带地区连续分级概率评分(CRPS评分)显著减小。就降水预报而言,从Brier评分与相对作用特征面积(AROC,Area under the Relative Operating Characteristics)的结果来看,SKEB方案有助于改善中国地区小雨[0.1 mm,10 mm)、中雨[10 mm,25 mm)与大雨[25 mm,50 mm)量级降水的概率预报技巧,而对暴雨[50 mm,∞)量级降水预报技巧影响很小(24 h降水量)。总体上,模式扰动随机动能补偿方案提高了GRAPES-GEPS的概率预报技巧。展开更多
In this paper, we construct two models for the searching task for a lost plane. Model 1 determines the searching area. We predict the trajectory of floats generated after the disintegration of the plane by using RBF n...In this paper, we construct two models for the searching task for a lost plane. Model 1 determines the searching area. We predict the trajectory of floats generated after the disintegration of the plane by using RBF neural network model, and then determine the searching area according to the trajectory. With the pass of time, the searching area will also be constantly moving along the trajectory. Model 2 develops a maritime search plan to achieve the purpose of completing the search in the shortest time. We optimize the searching time and transform the problem into the 0-1 knapsack problem. Solving this problem by improved genetic algorithm, we can get the shortest searching time and the best choice for the search power.展开更多
An irreducibly simple climate-sensitivity model is designed to empower even non-specialists to research the question how much global warming we may cause. In 1990, the First Assessment Report of the Inter- governmenta...An irreducibly simple climate-sensitivity model is designed to empower even non-specialists to research the question how much global warming we may cause. In 1990, the First Assessment Report of the Inter- governmental Panel on Climate Change （IPCC） expressed ＂substantial confidence＂ that near-term global warming would occur twice as fast as subsequent observation. Given rising CO2 concentration, few models predicted no wann- ing since 2001. Between the pre-final and published drafts of the Fifth Assessment Report, IPCC cut its near-term warming projection substantially, substituting ＂expert assessment＂ for models＇ near-term predictions. Yet its long-range predictions remain unaltered. The model indi- cates that IPCC＇s reduction of the feedback sum from 1.9 to 1.5 W m^-2 K^-1 mandates a reduction from 3.2 to 2.2 K in its central climate-sensitivity estimate; that, since feed- backs are likely to be net-negative, a better estimate is 1.0 K; that there is no unrealized global warming in the pipeline; that global warming this century will be 〈1 K;and that combustion of all recoverable fossil fuels will cause 〈2.2 K global warming to equilibrium. Resolving the discrepancies between the methodology adopted by IPCC in its Fourth and Fifth Assessment Reports that are highlighted in the present paper is vital. Once those dis- crepancies are taken into account, the impact of anthro- pogenic global warming over the next century, and even as far as equilibrium many millennia hence, may be no more than one-third to one-half of IPCC＇s current projections.展开更多
全球多区域可计算一般均衡模型(computable general equilibrium,CGE)是最重要的全球气候政策评估工具之一。该文给出了自主开发的全球多区域可计算一般均衡模型(global applied general equilibrium model,GAGE)的理论框架,描述了区域...全球多区域可计算一般均衡模型(computable general equilibrium,CGE)是最重要的全球气候政策评估工具之一。该文给出了自主开发的全球多区域可计算一般均衡模型(global applied general equilibrium model,GAGE)的理论框架,描述了区域内框架的地区账户收入分配方案和生产模块的嵌套结构以及区域间框架的国际贸易结构和2个虚拟国际机构的构建,即建立国际运输部门和国际银行用于描述国际贸易的运输服务供需以及投资的区域间流动。在标准GAGE模型的基础上进行了能源-环境-经济扩展,以描述能源与资本之间以及各类能源之间的替代关系。碳减排情景研究结果验证了GAGE模型理论框架的合理性,展示了能源替代对于减排潜力的显著影响。展开更多
Numerical weather prediction(NWP) is a core technology in weather forecast and disaster mitigation. China’s NWP research and operational applications have been attached great importance by the meteorological communit...Numerical weather prediction(NWP) is a core technology in weather forecast and disaster mitigation. China’s NWP research and operational applications have been attached great importance by the meteorological community.Fundamental achievements have been made in the theories, methods, and NWP model development in China, which are of certain international impacts. In this paper, the scientific and technological progress of NWP in China since1949 is summarized. The current status and recent progress of the domestically developed NWP system-GRAPES(Global/Regional Assimilation and Pr Ediction System) are presented. Through independent research and development in the past 10 years, the operational GRAPES system has been established, which includes both regional and global deterministic and ensemble prediction models, with resolutions of 3-10 km for regional and 25-50 km for global forecasts. Major improvements include establishment of a new non-hydrostatic dynamic core, setup of four-dimensional variational data assimilation, and development of associated satellite application. As members of the GRAPES system, prediction models for atmospheric chemistry and air pollution, tropical cyclones, and ocean waves have also been developed and put into operational use. The GRAPES system has been an important milestone in NWP science and technology in China.展开更多
文摘In this paper, we construct two models for the searching task for a lost plane. Model 1 determines the searching area. We predict the trajectory of floats generated after the disintegration of the plane by using RBF neural network model, and then determine the searching area according to the trajectory. With the pass of time, the searching area will also be constantly moving along the trajectory. Model 2 develops a maritime search plan to achieve the purpose of completing the search in the shortest time. We optimize the searching time and transform the problem into the 0-1 knapsack problem. Solving this problem by improved genetic algorithm, we can get the shortest searching time and the best choice for the search power.
文摘An irreducibly simple climate-sensitivity model is designed to empower even non-specialists to research the question how much global warming we may cause. In 1990, the First Assessment Report of the Inter- governmental Panel on Climate Change （IPCC） expressed ＂substantial confidence＂ that near-term global warming would occur twice as fast as subsequent observation. Given rising CO2 concentration, few models predicted no wann- ing since 2001. Between the pre-final and published drafts of the Fifth Assessment Report, IPCC cut its near-term warming projection substantially, substituting ＂expert assessment＂ for models＇ near-term predictions. Yet its long-range predictions remain unaltered. The model indi- cates that IPCC＇s reduction of the feedback sum from 1.9 to 1.5 W m^-2 K^-1 mandates a reduction from 3.2 to 2.2 K in its central climate-sensitivity estimate; that, since feed- backs are likely to be net-negative, a better estimate is 1.0 K; that there is no unrealized global warming in the pipeline; that global warming this century will be 〈1 K;and that combustion of all recoverable fossil fuels will cause 〈2.2 K global warming to equilibrium. Resolving the discrepancies between the methodology adopted by IPCC in its Fourth and Fifth Assessment Reports that are highlighted in the present paper is vital. Once those dis- crepancies are taken into account, the impact of anthro- pogenic global warming over the next century, and even as far as equilibrium many millennia hence, may be no more than one-third to one-half of IPCC＇s current projections.
文摘全球多区域可计算一般均衡模型(computable general equilibrium,CGE)是最重要的全球气候政策评估工具之一。该文给出了自主开发的全球多区域可计算一般均衡模型(global applied general equilibrium model,GAGE)的理论框架,描述了区域内框架的地区账户收入分配方案和生产模块的嵌套结构以及区域间框架的国际贸易结构和2个虚拟国际机构的构建,即建立国际运输部门和国际银行用于描述国际贸易的运输服务供需以及投资的区域间流动。在标准GAGE模型的基础上进行了能源-环境-经济扩展,以描述能源与资本之间以及各类能源之间的替代关系。碳减排情景研究结果验证了GAGE模型理论框架的合理性,展示了能源替代对于减排潜力的显著影响。
基金Supported by the National Key Research and Development Program of China(2017YFC1501900)Middle-and Long-term Development Strategic Research Project of the Chinese Academy of Engineering(2019-ZCQ-06)。
文摘Numerical weather prediction(NWP) is a core technology in weather forecast and disaster mitigation. China’s NWP research and operational applications have been attached great importance by the meteorological community.Fundamental achievements have been made in the theories, methods, and NWP model development in China, which are of certain international impacts. In this paper, the scientific and technological progress of NWP in China since1949 is summarized. The current status and recent progress of the domestically developed NWP system-GRAPES(Global/Regional Assimilation and Pr Ediction System) are presented. Through independent research and development in the past 10 years, the operational GRAPES system has been established, which includes both regional and global deterministic and ensemble prediction models, with resolutions of 3-10 km for regional and 25-50 km for global forecasts. Major improvements include establishment of a new non-hydrostatic dynamic core, setup of four-dimensional variational data assimilation, and development of associated satellite application. As members of the GRAPES system, prediction models for atmospheric chemistry and air pollution, tropical cyclones, and ocean waves have also been developed and put into operational use. The GRAPES system has been an important milestone in NWP science and technology in China.
