Temporal And Spatial Evolution Patterns And Influencing Factors Of Urban Heat Island And Air Quality In China

China has experienced rapid urbanization since the reform and opening up.Urban heat island effects and air pollution have become common environmental problems in urban areas,because they can affect the climate and ecological processes at the local,regional and national scales,and seriously endanger human physical health and social development.Therefore,in the recent years,the issue of urban heat island and air quality has become a hot issue for scientists,government policy makers and ordinary people.The study is based on 2004-2016 land use/cover change?LUCC?data,land surface temperature?LST?data,vegetation cover data,ground air quality montoring data,and other auxiliary data including surface elevation data,nighttime light data,meteorological data and socio-economic statistics data.Regional statistics,correlation analysis,regression analysis,global and regional spatial autocorrelation Moran's I index,exploratory spatial data analysis?ESDA?,ordinary least squares?OLS?,spatial lag model?SAR?and spatial error model?SEM?and geographic weighted regression?GWR?model were used.Quantitative study of the temporal and spatial distribution characteristics of surface urban heat island intensity?UHII?,air quality and air pollutants at city,regional and national scale in China.The temporal and spatial evolution,influencing factors and interrelationships of urban heat island and air quality are analyzed.The main research conclusions are as follows:?1?The spatial and temporal distribution pattern of UHII in China during 2016 shows that,during the daytime,in the southeastern of China?including Northeast,East China and South China?is higher than that of the northwest and north China.While the opposite at the nighttime,the northern regions are higher than the southern regions.The diurnal UHII have obvious seasonal charactertics.The air quality in southern China is better than that in the northern region in 2016.Particle pollution was the main pollutant in China.The air quality in the North China Plain was the worest,and the concentrations of NO₂ and O₃ in larger cities were higher.The phenomenon of SO₂ exceeding the standard appears mostly in provinces with high coal consumption such as Shanxi,Shandong and Liaoning province.?2?The urban heat island and air quality have significant spatial autocorrelation.The relationship between urban heat island and air quality and incluncing factors is analyzed by using different spatial regression models.The results show that the GWR model has higher fitness than other spatial model.The urban form is closely related to the urban heat island and air quality.The larger mean patch area,the more complex shape of the city,the higher connectivity,the stronger UHII and the lower average air pollutants concentration.The relationship between urbanization indicators and NO₂ concentration is closest,and the degree of economic development has a significant positive correlation with NO₂ concentration.City with large population density particulate matter is more serious.?3?During 2004-2016,there were no significant changes in the diurnal UHII of 31major cities in China,but the surface temperatue showed an obvious upward trend,and the vegetation coverage of large cities increased.The rate of warming of urban surface temperature at the night is 0.09?/a faster than daytime of 0.06?/a.Overall,the increase of urban surface temperature and the increase of urban area,population size and corresponding energy consumption.?4?During 2004-2016,the air quality of 31 major cities showed a good-deteriorating-improve trend.Benefit from the implementation of environmental protection policies and the improvement of vegetation coverage,large cities showed obvirous signs of improvement,such as Beijing,Shanghai and Guangzhou has improved significantly.The innovation of this research is that it analyzes the spatial and temporal distribution pattern and influencing factors of urban heat island and air quality in China at the national scale,and investigated the relationship between urban heat island and air quality.Multi-source data set and GWR model are used to mine the spatial distribution of influencing factors from a geographical perspective.At present,the research belongs to a new concept,which provides a reference for further research on relationship between urban heat island and air quality.In summary,this study uses remote sensing data and ground observation data,to use spatial regression model to comprehensively analyze the spatial and temporal changes and influencing factors of urban heat island and air quality under the urbanization process in China.Urban areas are a combination of urban form and population,the intersection of matter and energy,which has a significant impact on urban heat island effect and air quality.With the development of economy,adjustment of energy structure,elevation of vegetation coverage and advanced technology implementation,urbanization can provide technical and economic measures to alleviate urban heat island effects and air pollution.The results of this study can provide reference for urban planning,environmental protection policy formulation and related researchers.