Study On The Influence Of The Spatial Pattern Of Land Use On The Intensity Of Urban Heat Island In Baoji City Based On Landsat Image

With the accelerating process of urbanization,in order to pursue urban construction and development,many cities blindly adopt "pancake" expansion mode,occupying forestland,cultivated land and other resources to build residential areas,transportation land and other construction land.This way of disorderly expansion makes the urban land use spatial pattern gradually unreasonable and it has a negative impact on the urban ecological environment.In addition,a large number of greenhouse gases and particulate matter in the daily production and life of the city lead to the rising trend of the city's heat island effect in a short period of time,which seriously affects the living environment of urban residents,even to the health of the urban residents.In view of the present situation,through exploring the impact of the spatial pattern of land use on the intensity of urban heat island,it can better layout the structure of land use and optimize the spatial pattern of land use.Therefore,it has important practical significance to do the research work in this paper.In this paper,the spatial pattern of land use and the intensity of heat island in Baoji in 2007 and 2015 are explored,and the interaction between the spatial pattern of land use and the intensity of urban heat island is clarifying,and the effective countermeasures for the optimization of the spatial distribution of land use in Baoji are put forward.Using the supervised classification method,the land use type data of Baoji two periods are extracted,and the change of land use type in this period is statistically analyzed.The surface temperature data,the normalized vegetation index and the vegetation cover information of the study area were extracted by using the radiative transfer equation method,and the surface temperature data,the normalized vegetation index and the vegetation cover information of the study area were extracted.The change of surface temperature,the change of vegetation cover and the change of the heat island effect in Baoji city from 2007 to 2015 were determined.On this basis,the two periods of land use type data and surface temperature data are added to analyze the impact of the spatial pattern of land use on the intensity of the heat island.Through the above research work,we get the following research results.(1)Surface temperature data and heat island intensity distribution data for Baoji City in 2007 and 2015 show that the heat island effect has undergone major changes during the period from 2007 to 2015 in Baoji City.In the three main urban districts of Jintai District,Chencang District and Weibin District,the heat island effect has expanded and its intensity has increased.(2)The change direction of the heat island effect is basically the same as that of the spatial pattern of land use change.The significant increase in the number of land for construction use has a significant increase in the heat island effect.(3)Through the analysis of the relationship between land use type and surface temperature,it can be found that the surface temperature of each land use type from high to low is unused land,construction land,cultivated land,grassland,water area and woodland.From the strong green island area to the strong heat island area,the proportion of woodland and water gradually declined,while the proportion of construction land and unused land gradually increased,and the increase was very obvious.(4)The NDVI value of forest land is the highest,while the NDVI value of construction land and unused land is generally low.In addition to water,the region with higher NDVI value coincides with the region where the heat island effect is weak,and the lower NDVI region coincides with the region with stronger heat island effect.