Impact Of Urban Construction Factors On Urban Climate

Urbanization and climate change have been one of the most hottest topic in the world nowadays,On the one hand,climate change has caused extreme precipitation,high temperature and other extreme weather phenomenon,leading the city system to various economic and social losses including the risk of the melting of polar glacier to coastal low altitude area,on the other hand,urbanization has changed urban land use intensity,land use types and so on because of the population aggregation,which led to the changes in urban surface and the changes in urban evapotranspiration,affecting the formation of urban heat island,urban rain island,urban dry island and other specific phenomenon of the city.Shanghai is regarded as a representative of the study area because of the earlier urbanization process and rapid international metropolis.Based on the theories of urban planning,meteorology and geography,this paper focuses on the interaction between urbanization and climate change.The research focus are as follows:In the first part,based on the meteorological data of 11 meteorological stations in Shanghai from 2000 to 2014,the four most commonly used indicators of climate,temperature,precipitation,relative humidity and maximum wind speed were selected.On the spatial scale,we use the method of spatial interpolation to compare the temporal and spatial differences of the meteorological elements in Shanghai.On the time scale,we can statistically analyze the meteorological elements of 11 meteorological stations over the years and understand the temporal changes of meteorological elements in each region.Finally,we discussed the reasons depending on space and time analysis and the actual situation of Shanghai.Urban meteorological factor analysis and time scale statistics show that the temperature rises gradually from 2000 to 2014,the precipitation intensity and frequency increased,the relative humidity of the city decreases,and the maximum wind speed decreases year by year.On the spatial scale,the meteorological elements were found to be more prominent in the city center and in some suburban areas where urbanization developed more rapidly,such as some regions of Pudong,Minhang and Songjiang.In the second part,based on the characteristics of Shanghai climate,we try to explore the main factors that influence the urban climate.We construct the urbanization-human activity model from social,economic,nature and environment dimensions.The factors influencing the climate effect were selected by quantitative analysis(standardized,coefficient of variation to determine the coefficient of variation,and the weight of the index)to select the factors that had the greatest impact on the climate effect.The quantitative analysis shows that the urban green area,the urban built-up area,the population density and the road density are the most obvious factors for the urban climate effect,and the weights are 0.184,0.138,0.116 and 0.110 respectively.The increase of population density and road density will affect the increase of artificial exhaust and hardening pavement.The change of urban built area affects the nature of urban surface,and the urban green area will reduce the urban temperature by enhancing transpiration,all of those can influence urban climate.In the third part,we implemented spatial analysis to urbanization factor,population density is from the fifth population census and sixth population census data,Road density presented through the GIS spatial calculation,urban built-up area Using Albedo remote sensing inversion method to reflect the expansion of Shanghai built area.The urban green area is symbolized by the NDVI remote sensing inversion mode.At the same time,through the diagonal profile of Shanghai,the urbanization factors of Shanghai streets were distinguished and changed.The spatial results showed that the population density of Shanghai central city decreased,and the population around the main city and suburban city showed a trend of increasing.The road density and urban built-up areas show a trend of increasing year by year,the urban green area is less distributed,in recent years there is an upward trend.The fourth part explores the interaction between urbanization and climatic factors.First,the urbanization factors(urban population density,urban road density,urban built-up area changes,urban green area)is divided into five categories,then give weight and layer stacking,raster urbanization comprehensive analysis.Through the statistical analysis in ArcGIS,the highest urbanization area can be obtained,the corresponding annual average temperature is the highest,the annual precipitation is the highest,the annual relative humidity is the lowest,The annual maximum wind speed is the lowest and vice versa.It is beneficial for the cities to formulate the adaptive countermeasures to deal with climate change,and to provide suggestions for creating ecological livable cities.