Research On Reconstruction Of Air Duct System Of Urban Agglomeration Base On Haze Control

By the end of 2017,China's overall urbanization rate has reached 58.5%,and Zhejiang's urbanization rate has reached 68.0%,an increase of 54 percentage points compared with the initial stage of Chinese economic reform.With the rapid development of urbanization,a large number of people are pouring into the city,the scale of the city is expanding,and the construction land is expanding constantly,thus squeezing the ecological space,and the urban climate and environment are facing tremendous pressure.In the period of high-speed economic growth in China,the ecological red line is often conceded to economic development,Unreasonable land use and unstrict ecological control are accelerated to worsen the relationship between human and nature,eventually leading to regional environmental problems,especially frequent haze pollution,has become a hot issue of concern.Wind duct is a special spatial structure of land use.Regional wind duct across administrative boundaries can effectively induce wind and drive haze,alleviate haze pollution and improve air quality,but it is often neglected in the past spatial planning.Based on the traditional wind tunnel construction mode,this paper proposes a method to coordinate the ventilation demand of different cities,which combines remote sensing inversion and GIS technology to identify and reconstruct the regional wind channel.It not only identifies and excavates the narrow wind channel composed of tangible objects,but also makes full use of natural landscapes to construct the generalized wind channel.On this basis,taking the urban agglomeration around Hangzhou Bay as an example which has high urbanization level and complicated underlying surface,and suffering with serious haze pollution.By means of remote sensing inversion and GIS spatial analysis,and combining with the literature,the wind environment,fog and haze spatial and temporal distribution,surface temperature distribution,ventilation demand of each city and the overall climate environment of the urban agglomeration are comprehensively grasped and evaluated.The three major components of the wind duct system are compensation space,action space and air duct.Through in-depth analysis and one by one identification,the fog and haze control strategy based on wind channel reconstruction and land use spatial optimization is finally obtained.The results show that:(1)The climate and environment problems of urban agglomeration are serious.The autumn and winter are the high-incidence season of haze in the study area,and there is a "V" haze belt.The intersection point is located in Hangzhou.The phenomenon of heat island in urban agglomeration is obvious in summer,and the strong heat island is located in the central area of Hangzhou,Shaoxing and Ningbo.2.Due to urban development,expansion of construction land and reclamation,the original natural ventilation system of urban agglomeration has been destroyed to a great extent,which is manifested in the expansion of the function space in the air duct system,the squeeze of compensation space and the occupation of compensation space.Three aspects of air duct space obstruction are put forward.3.The assumption of air duct reconstruction and suggestions for space optimization in urban agglomeration are put forward,including three main air ducts,multiple secondary air ducts,multiple category I and II compensation spaces and key ventilation action spaces divided by scale and influence range.The wind duct system including compensation space and action space leads to the problem of how to coordinate the planning of regional and urban wind ducts.The method of regional wind channel identification and reconstruction proposed in this paper can be applied to the overall optimization of wind environment in the study area with prominent climate and environment problems.Aiming at the problem of regional haze management and control,it provides decision support for environmental protection,meteorology and natural resources departments,and promotes the sustainable development of urban agglomerations and the construction of production,living and ecological space.