Over the past decades,a large number of studies have been carried out in the field of urban meteorology in China.This paper summarizes the main progress in urban meteorology research from four aspects:urban meteorolog...Over the past decades,a large number of studies have been carried out in the field of urban meteorology in China.This paper summarizes the main progress in urban meteorology research from four aspects:urban meteorological observation network and field campaign,multi-scale model of urban meteorology,interaction between urban meteorology and atmospheric environment,and the impacts of urbanization on weather and climate.Major advances are as follows.China’s major cities have established or are improving comprehensive urban meteorological observation networks characterized by multi-platform,multi-variable,multi-scale,multi-link,and multi-function.Beijing,Nanjing,Shanghai,and other cities carried out urban meteorological field campaigns,which were included in the WMO research demonstration project.Wind tunnel experiments and scale-model outdoor experiments were successfully conducted.Multi-scale urban meteorological and air quality prediction numerical model systems have been developed and put into operational use.The urban heat island effect;urban impacts on precipitation,regional climate,and air quality;urban planning;and interaction between urban meteorology and atmospheric environment are extensively investigated.Finally,efforts to improve observational technology,data assimilation,and urban system modeling,to explore the impacts of urbanization on environment and human health,and to provide integrated urban hydro-meteorological climate and environmental services are planned ahead.展开更多
流变场分配(flow field partitioning)现象在自然界高应变岩石中十分常见。传统的基于固体连续变形机制理论的变形分析中,流变场分配问题往往被忽略,致使应变带中流变场如何分配一直都缺乏深入认识。Eshelby阐述了嵌入均匀介质中的椭球...流变场分配(flow field partitioning)现象在自然界高应变岩石中十分常见。传统的基于固体连续变形机制理论的变形分析中,流变场分配问题往往被忽略,致使应变带中流变场如何分配一直都缺乏深入认识。Eshelby阐述了嵌入均匀介质中的椭球体内流变场的数学方法,为探讨流变场的分配奠定了理论基础。本文从固体连续变形机制入手,重点介绍基于Eshelby理论的多尺度数值模拟思路和方法,探讨流变场分配问题。模拟结果表明:嵌入基质中的椭球体内分布的流变场主要取决于椭球体与基质间的相对流变强度,椭球体的相对流变强度越低,其变形越接近于简单剪切,且有限应变积累越快。模拟还揭示,不同流变强度的椭球体内模拟拉伸线理和面理产状的总体格局反映基质流变场特征。由此得到以下结论:(1)在流变场分配现象显著的区域,局部小尺度上应变、涡度测量分析结果无法直接揭示区域流变场运动学边界条件,对这些区域的构造变形分析必须是多尺度的;(2)基于Eshelby理论的以实质变形组构为约束的多尺度数值模拟分析,能更为合理地揭示高应变岩石中流变场的分配。展开更多
基金Supported by the National Natural Science Foundation of China(41775047 and 41425020)Young Beijing-Scholars Program。
文摘Over the past decades,a large number of studies have been carried out in the field of urban meteorology in China.This paper summarizes the main progress in urban meteorology research from four aspects:urban meteorological observation network and field campaign,multi-scale model of urban meteorology,interaction between urban meteorology and atmospheric environment,and the impacts of urbanization on weather and climate.Major advances are as follows.China’s major cities have established or are improving comprehensive urban meteorological observation networks characterized by multi-platform,multi-variable,multi-scale,multi-link,and multi-function.Beijing,Nanjing,Shanghai,and other cities carried out urban meteorological field campaigns,which were included in the WMO research demonstration project.Wind tunnel experiments and scale-model outdoor experiments were successfully conducted.Multi-scale urban meteorological and air quality prediction numerical model systems have been developed and put into operational use.The urban heat island effect;urban impacts on precipitation,regional climate,and air quality;urban planning;and interaction between urban meteorology and atmospheric environment are extensively investigated.Finally,efforts to improve observational technology,data assimilation,and urban system modeling,to explore the impacts of urbanization on environment and human health,and to provide integrated urban hydro-meteorological climate and environmental services are planned ahead.
文摘流变场分配(flow field partitioning)现象在自然界高应变岩石中十分常见。传统的基于固体连续变形机制理论的变形分析中,流变场分配问题往往被忽略,致使应变带中流变场如何分配一直都缺乏深入认识。Eshelby阐述了嵌入均匀介质中的椭球体内流变场的数学方法,为探讨流变场的分配奠定了理论基础。本文从固体连续变形机制入手,重点介绍基于Eshelby理论的多尺度数值模拟思路和方法,探讨流变场分配问题。模拟结果表明:嵌入基质中的椭球体内分布的流变场主要取决于椭球体与基质间的相对流变强度,椭球体的相对流变强度越低,其变形越接近于简单剪切,且有限应变积累越快。模拟还揭示,不同流变强度的椭球体内模拟拉伸线理和面理产状的总体格局反映基质流变场特征。由此得到以下结论:(1)在流变场分配现象显著的区域,局部小尺度上应变、涡度测量分析结果无法直接揭示区域流变场运动学边界条件,对这些区域的构造变形分析必须是多尺度的;(2)基于Eshelby理论的以实质变形组构为约束的多尺度数值模拟分析,能更为合理地揭示高应变岩石中流变场的分配。
