Study On The Characteristics And Optimization Of High-temperature Heat Wave Disaster In Mountainous High-density Urban Space

Human activities continue to affect global warming,which brings about more and more serious global climate change.The frequency and intensity of extreme high temperature heat wave are increasing,and the fatality rate of high temperature heat wave disaster is increasing.The heat disaster caused by high temperature is also one of the most serious disasters in our country.More than one-third of the country's cities are mountainous cities,which are subject to the influence of special topography and development patterns,and the combined influence of multiple factors has led to a prominent problem of high temperature and heat wave disasters in mountainous and high-density cities,the urban space has a high impact on the high temperature heat wave disaster,so the research on the spatial optimization of high-density mountain cities oriented to the mitigation of high temperature heat wave has been focused on.Therefore,in this paper,the Central City of Chongqing is taken as the typical representative of high-density city in mountainous area,and the relationship between it and high-temperature heat wave is explored through the selection of the key elements of urban space,based on this,urban space optimization strategy and thermal disaster management system are put forward.This paper is divided into three parts,the first part(chapter 2)of the impact of high-temperature heat wave disaster of urban space elements.By combining the present situation of high temperature heat wave disaster with the main spatial characteristics of the city,the key factors are urban land use status,the main type of urban land cover--green space and water system,and the representation of urban space shape —— urban local climate zone(LCZ).The spatial distribution characteristics of the central urban area of Chongqing are analyzed by using the three key spatial factors mentioned above.The second part(chapter three-chapter four)studies the spatial characteristics of mountain high-density city and its relationship with high temperature heat wave.The study is divided into two scales: 1)large scale study on the relationship between urban land surface temperature and spatial factors,selecting the key urban spatial factors in the study area,and analyzing the correlation between each factor and land surface temperature;The distribution characteristics of urban space heat disaster are that the present situation of urban land use and the building function have the most strong influence on the distribution of high temperature heat wave,the effect of alleviating the high temperature heat wave of large-scale greenbelt water system such as Liangjiang city is very remarkable,and the multi-factors such as building height and density in local climatic division affect the distribution of heat disaster.2)taking Jiefang Stele in Yuzhong District as an example,the climate monitoring and human subjective thermal comfort experiment were carried out during the urban heat wave,the relationship between urban thermal environment and different spatial form was analyzed,and the relationship between different spatial form and urban heat wave was explored.In the third part(Chapter 5),in order to alleviate the urban high temperature heat wave,the optimization strategy of urban space to deal with the high temperature heat wave disaster is put forward,the strategy consists of two parts: 1)urban space and form optimization strategy which is mainly to mitigate the heat wave disaster.The strategy of urban land use optimization includes the layout of different functional areas and the planning of ecological cold source,the optimization of urban green space includes the establishment of urban greening network,and the optimization strategy of urban spatial form includes the adjustment of the layout and height of different functional buildings.2)planning and management system of heat disaster to improve the ability of city to deal with high temperature heat wave.Based on the latest research progress in dealing with high-temperature heat wave disaster in the world,this paper summarizes the control mechanism and planning measures of high-temperature heat wave disaster,and from two aspects of “High-temperature heat wave early warning system” and“Heat Health Action Plan”,puts forward the establishment of “Emergency Response Plan +long-term prevention and control plan” coordinated operation mechanism and system construction.