Beijing's green belt policy is three-fold:fi rstly to protect farmers' interests during urbanization, secondly to control the urban expansion, and thirdly to improve the ecological environment. The planning of...Beijing's green belt policy is three-fold:fi rstly to protect farmers' interests during urbanization, secondly to control the urban expansion, and thirdly to improve the ecological environment. The planning of industrial land for green belts has thus emerged as a way to help achieve these goals during Beijing's urban growth from morphological, social, and economic perspectives. First of all, this paper introduces the implementation mechanisms of the planning of industrial land for green belts, from which it abstracts a model of land adjustment and urban-rural cooperation. Secondly, the paper analyzes the effects and current dilemmas during the implementation of the planning of industrial land for green belts. Thirdly, results are compared with other spontaneously developed industries in the rural-urban fringe area to illustrate the changes brought about by the planning. Finally, the paper proposes three measures for future improvement, including balancing the industrial land use quotas between different townships, conducting cooperative land adjustment, and encouraging spontaneously developed industrial projects.展开更多
合理设置道路绿化带能够改变街道空气流场进而改善空气质量。利用风洞试验结合数值模型的方法测试了树冠形状和绿化带位置对街道峡谷的风场影响。在数值模型中,采用针对植物模型不同高度赋予不同叶面积密度(leaf area density,LAD)值的...合理设置道路绿化带能够改变街道空气流场进而改善空气质量。利用风洞试验结合数值模型的方法测试了树冠形状和绿化带位置对街道峡谷的风场影响。在数值模型中,采用针对植物模型不同高度赋予不同叶面积密度(leaf area density,LAD)值的新方法近似模拟不同树冠形状的植物,通过输入污染源数据,得到风场及污染物浓度数据结果;与风洞试验结果进行对比,验证了其有效性;进而,利用数值模型分析了不同绿化带设置下街道峡谷内行人的污染暴露特征,结果表明:绿化带位置及树冠形状影响街道峡谷中的涡流结构,形成复杂的细小湍流,从而影响街道峡谷中的风环境和污染物分布。阔叶树冠和位于街道峡谷中央的绿化带位置有利于降低行人污染暴露风险。未来研究中,通过增加风洞试验布点、考虑热力作用及气象因子的影响,或许可以提供更加详细的改善街道峡谷微环境的绿化带布局,为城市大气环境管理和绿地系统建设提供科学依据。展开更多
文摘Beijing's green belt policy is three-fold:fi rstly to protect farmers' interests during urbanization, secondly to control the urban expansion, and thirdly to improve the ecological environment. The planning of industrial land for green belts has thus emerged as a way to help achieve these goals during Beijing's urban growth from morphological, social, and economic perspectives. First of all, this paper introduces the implementation mechanisms of the planning of industrial land for green belts, from which it abstracts a model of land adjustment and urban-rural cooperation. Secondly, the paper analyzes the effects and current dilemmas during the implementation of the planning of industrial land for green belts. Thirdly, results are compared with other spontaneously developed industries in the rural-urban fringe area to illustrate the changes brought about by the planning. Finally, the paper proposes three measures for future improvement, including balancing the industrial land use quotas between different townships, conducting cooperative land adjustment, and encouraging spontaneously developed industrial projects.
文摘合理设置道路绿化带能够改变街道空气流场进而改善空气质量。利用风洞试验结合数值模型的方法测试了树冠形状和绿化带位置对街道峡谷的风场影响。在数值模型中,采用针对植物模型不同高度赋予不同叶面积密度(leaf area density,LAD)值的新方法近似模拟不同树冠形状的植物,通过输入污染源数据,得到风场及污染物浓度数据结果;与风洞试验结果进行对比,验证了其有效性;进而,利用数值模型分析了不同绿化带设置下街道峡谷内行人的污染暴露特征,结果表明:绿化带位置及树冠形状影响街道峡谷中的涡流结构,形成复杂的细小湍流,从而影响街道峡谷中的风环境和污染物分布。阔叶树冠和位于街道峡谷中央的绿化带位置有利于降低行人污染暴露风险。未来研究中,通过增加风洞试验布点、考虑热力作用及气象因子的影响,或许可以提供更加详细的改善街道峡谷微环境的绿化带布局,为城市大气环境管理和绿地系统建设提供科学依据。
