This paper, taking Hexi Corridor as an example, analyzes the altemating intimidation and the dynamic evolving relation between urbanization and eco-environment in arid area of West China. We argue that the harmonious ...This paper, taking Hexi Corridor as an example, analyzes the altemating intimidation and the dynamic evolving relation between urbanization and eco-environment in arid area of West China. We argue that the harmonious development system of the urbanization and eco-environment would go through four phases： rudimentary symbiotic phase, harmonious developmental phase, utmost increasing phase and spiral type rising phase. Throughout the four phases, the elements of the system would influence each other, coerce each other, and complete the spiral type rising process from low-grade symbiosis to high-grade harmony together. The study on Hexi Corridor shows that the urbanization level in Hexi Corridor has increased gradually from 1985 to 2003 accompanied with the fluctuations of eco-environment state. The response of eco-environment to urbanization has been evident, but lagged behind the urbanization course. At present, the harmonious development system in Hexi Corridor was in its harmonious developmental phase. However, the coupling degree has increased quickly and approached 90 yet, which is signaling that the system is about to enter the utmost increasing phase, and the ecological crisis will enter the latent period. We have found that the coupling degree can well reflect the interactive coercing and dynamic evolving situation between urbanization and eco-environment in Hexi Corridor. From the temporal change of the coupling degree, it can be concluded that urbanization sometimes needs to pay a certain cost for the damage of the eco-environment in its initial stages, but as the urbanization continues, the state of the eco-environment would be meliorated.展开更多
In this paper, some experimental studies on the impact of effluent from an exhaust tower of an underground tunnel with special construction are reported. By measuring the flow field downstream of the tower in NJU mete...In this paper, some experimental studies on the impact of effluent from an exhaust tower of an underground tunnel with special construction are reported. By measuring the flow field downstream of the tower in NJU meteorological wind tunnel, some flow characteristics in the make area were established. Based on these, an advanced random\|walk dispersion model was set up and applied successfully to the simulation of dispersion in the wake area. The modelling results were in accordance with wind tunnel measurements. The computed maximum of ground surface concentration in the building case was a factor of 3-4 higher than that in the flat case and appeared much closer to the source. The simulation indicated that random walk modelling is an effective and practical tool for the wake stream impact assessment.展开更多
该文主要介绍了科技部国家重点基础研究发展规划项目“首都北京及周边地区大气、水、土环境污染机理及调控原理”大气分项目的研究成果。项目分别于2001年和2003年重点开展了BECAPEX科学试验(Beijing City AirPollution Experiment)。BE...该文主要介绍了科技部国家重点基础研究发展规划项目“首都北京及周边地区大气、水、土环境污染机理及调控原理”大气分项目的研究成果。项目分别于2001年和2003年重点开展了BECAPEX科学试验(Beijing City AirPollution Experiment)。BECAPEX试验同步进行城市边界层气象与大气化学观测,通过卫星遥感、地面观测,即城市空间和地面以及点与面结合的技术途径,以揭示北京城市污染“空气穹隆”大气化学结构特征及其变化规律,为城市环境大气动力-化学模式提供基本科学参数,给出城市边界层大气物理化学过程综合模型,为提高城市环境大气物理-化学过程耦合模式的准确性和可靠性提供科学依据。该项目揭示了北京城区和城近郊区城市边界层结构与湍流特征,城市大气污染垂直结构特征;发现了城市大气污染空间结构多尺度特征,其中包括大气污染源影响和城市热岛多尺度特征;揭示了城市大气重污染过程周边源影响域,以及北京及周边地区气溶胶影响域和区域气候响应;提出了北京市典型污染源排放清单;发展了城市气象模式系统,包括冠层模式、街谷环流和热力结构以及城市高大建筑群周围风环境数值模拟;发展了空气质量模式技术,包括二次气溶胶模拟试验、北京地区SO2污染的长期模拟及不同类型排放源影响的计算与评估、影响北京地区的沙尘暴输送模拟、区域化学输送模式中NOx和O3源示踪法,城市尺度的大气污染CAPPS模式及统计模型的应用、大气污染及紫外辐射数值预报模式和CMAQ-MOS空气质量预报方法;改进了美国公共多尺度空气质量预报模式,建立了CMAQ-MOS区域空气质量动力-统计模型预报模式,以及发展的源同化技术,突破了当前空气质量模式技术“瓶颈”,使模式预报准确率明显提高。展开更多
基金NationalNaturalScience Emphases Foundation ofChina,No.40335049NationalNaturalScience Foundation ofChina,No.40471059
文摘This paper, taking Hexi Corridor as an example, analyzes the altemating intimidation and the dynamic evolving relation between urbanization and eco-environment in arid area of West China. We argue that the harmonious development system of the urbanization and eco-environment would go through four phases： rudimentary symbiotic phase, harmonious developmental phase, utmost increasing phase and spiral type rising phase. Throughout the four phases, the elements of the system would influence each other, coerce each other, and complete the spiral type rising process from low-grade symbiosis to high-grade harmony together. The study on Hexi Corridor shows that the urbanization level in Hexi Corridor has increased gradually from 1985 to 2003 accompanied with the fluctuations of eco-environment state. The response of eco-environment to urbanization has been evident, but lagged behind the urbanization course. At present, the harmonious development system in Hexi Corridor was in its harmonious developmental phase. However, the coupling degree has increased quickly and approached 90 yet, which is signaling that the system is about to enter the utmost increasing phase, and the ecological crisis will enter the latent period. We have found that the coupling degree can well reflect the interactive coercing and dynamic evolving situation between urbanization and eco-environment in Hexi Corridor. From the temporal change of the coupling degree, it can be concluded that urbanization sometimes needs to pay a certain cost for the damage of the eco-environment in its initial stages, but as the urbanization continues, the state of the eco-environment would be meliorated.
文摘In this paper, some experimental studies on the impact of effluent from an exhaust tower of an underground tunnel with special construction are reported. By measuring the flow field downstream of the tower in NJU meteorological wind tunnel, some flow characteristics in the make area were established. Based on these, an advanced random\|walk dispersion model was set up and applied successfully to the simulation of dispersion in the wake area. The modelling results were in accordance with wind tunnel measurements. The computed maximum of ground surface concentration in the building case was a factor of 3-4 higher than that in the flat case and appeared much closer to the source. The simulation indicated that random walk modelling is an effective and practical tool for the wake stream impact assessment.
文摘该文主要介绍了科技部国家重点基础研究发展规划项目“首都北京及周边地区大气、水、土环境污染机理及调控原理”大气分项目的研究成果。项目分别于2001年和2003年重点开展了BECAPEX科学试验(Beijing City AirPollution Experiment)。BECAPEX试验同步进行城市边界层气象与大气化学观测,通过卫星遥感、地面观测,即城市空间和地面以及点与面结合的技术途径,以揭示北京城市污染“空气穹隆”大气化学结构特征及其变化规律,为城市环境大气动力-化学模式提供基本科学参数,给出城市边界层大气物理化学过程综合模型,为提高城市环境大气物理-化学过程耦合模式的准确性和可靠性提供科学依据。该项目揭示了北京城区和城近郊区城市边界层结构与湍流特征,城市大气污染垂直结构特征;发现了城市大气污染空间结构多尺度特征,其中包括大气污染源影响和城市热岛多尺度特征;揭示了城市大气重污染过程周边源影响域,以及北京及周边地区气溶胶影响域和区域气候响应;提出了北京市典型污染源排放清单;发展了城市气象模式系统,包括冠层模式、街谷环流和热力结构以及城市高大建筑群周围风环境数值模拟;发展了空气质量模式技术,包括二次气溶胶模拟试验、北京地区SO2污染的长期模拟及不同类型排放源影响的计算与评估、影响北京地区的沙尘暴输送模拟、区域化学输送模式中NOx和O3源示踪法,城市尺度的大气污染CAPPS模式及统计模型的应用、大气污染及紫外辐射数值预报模式和CMAQ-MOS空气质量预报方法;改进了美国公共多尺度空气质量预报模式,建立了CMAQ-MOS区域空气质量动力-统计模型预报模式,以及发展的源同化技术,突破了当前空气质量模式技术“瓶颈”,使模式预报准确率明显提高。
