Research On The Construction Of Ventilation Corridor In Downtown Based On Urban Green Space System

After the reform and opening up,with the country's high economic development,the construction of cities has become more and more rapid,showing a rapid expansion of the incremental planning stage.The rapid development of cities often neglects the environmental problems of urban development.Environmental problems brought about by human production and life,including heat island effect and haze,are seriously affecting human life.Nowadays,urban construction has slowed down and entered the stage of stock planning,but these urban environmental problems are still the hot issues concerned by researchers.How to effectively alleviate the heat island effect and urban air pollution by building a city ventilation corridor system with high ventilation efficiency and good air quality is the main content of this paper.Firstly,this paper reviews the relevant research at home and abroad,and summarizes that most of the researchers use CFD technology or GIS platform to simulate the relevant data,and construct ventilation corridor by analyzing the factors of urban surface roughness,urban climate and so on.On this basis,the composition of Urban Ventilation corridor is analyzed,which consists of three parts: action space,compensation space and air guide channel.According to the theory of urban green space system,the main factors affecting urban ventilation corridor are urban wind direction,ecological cold source and surface roughness.Secondly,taking the central city of Guangzhou as the research area,this paper analyses the basic situation of Guangzhou,including geographical conditions,wind direction,surface temperature,etc.,and proposes a research idea based on quantitative analysis of multiple index factors to simulate potential ventilation corridors by using four-level analysis method for ventilation performance.Taking the ventilation performance of Urban Ventilation corridors as the target layer,the index domains are selected and analyzed from two dimensions of ventilation efficiency and air quality,including five indicators: terrain,road network,building,water system and green space.Then one or more index factors are selected on the index layer to quantify the selected indicators of the index domains.Variation coefficient method is used to determine the weight of each index factor.Then,five index factors are superposed and analyzed by ENVI5.3,Rhino 6 parameterization,GIS and other analysis tools.The grid cost and minimum cost path are calculated by the minimum cost path method,and the potential ventilation corridor in the central urban area of Guangzhou City is simulated.Finally,we pay attention to the relationship between green space system and the spatial layout of ventilation corridors,and draw the conclusion that the combination of the former block,wedge-shaped space and line,circular space and the latter compensation space and air guide space,and the latter can improve the ecological function of the former.Based on this connection,we extract the potential wind corridors and construct eight main wind corridors and 16 sub-wind corridors of Urban Ventilation corridors.The location,scale and main functions of the system are suggested.From the aspects of scale control,space control,air inlet and cold source control,as well as their influence scope,this paper puts forward specific suggestions on the construction of Urban Ventilation corridor system.The innovation of this paper is to select five indicators as the evaluation index of Urban Ventilation corridor by four levels of indicators,and to select the old urban area of Guangzhou,which is a mature urban construction,as the research area,to discuss the planning of ventilation corridor,and to reconstruct the evaluation system of Urban Ventilation corridor,so as to ensure the effectiveness of ventilation of Urban Ventilation corridor.On the premise,innovatively focusing on the air quality of ventilation corridor airflow,taking the vegetation coverage as the characterization of the impact of vegetation on the air quality of ventilation corridor,and according to the simulation results,the paper puts forward the method of linking urban green space system with the spatial layout of Urban Ventilation corridor,which provides a new idea for the future study of Urban Ventilation corridor.