Research On The Urban Heat Island Effect In Changchun City Based On Remote Sensing Technology

Cities are the inevitable result of the development of human civilization.With the acceleration of the process of urbanization,human behavior activities have also brought an unavoidable impact on the natural society.The rapid development of science and technology,the acceleration of the process of industrialization,the continuous progress of society,and the gradual improvement of human living standards have more or less brought many ecological and environmental problems to the city that cannot be ignored.The population in the city is increasing year by year,the artificial building community is increasing day by day,and the structure and type of the underlying surface of the city are changing;the original vegetation,agriculture,forestry and water body are reduced,replaced by impervious surfaces such as asphalt roads and cement roads,compared with vegetation coverage As far as the soil is concerned,this impervious surface will store more heat,and then disperse the heat into the atmosphere.Accompanied by various factors such as air pollution,automobile exhaust,and greenhouse effect,heat accumulates in the urban area,which will eventually lead to the urban area.The surface temperature in the interior is higher than that in the suburbs,forming an urban heat island effect.This study selects remote sensing images from the summer of 2014 to 2018,based on Landsat 8 OLI/TIRS remote sensing data,and uses a single-window algorithm to invert the surface temperature on the Arc GIS 10.5 software platform;combined with land use and land cover types,The intensity of the heat island in Changchun City is divided into different levels;with the administrative area as the boundary,the change trend of the surface temperature and the heat island effect of the administrative area in the past five years is analyzed.The main conclusions are as follows:(1)The inversion results of surface temperature in Changchun City show that from2014 to 2018,the minimum temperature,maximum temperature and average temperature showed an increasing trend.The average temperatures in the five years were 29.31?,30.66?,30.85?,31.04?,and 31.39?.From the perspective of spatial distribution,the heat island effect in Changchun City is already very significant.The core area of the heat island is mainly in the railway station area,the north of Kuancheng District,the south of Lvyuan District,and the north of Nanguan District.(2)The land cover types of Changchun City in 2018 can be reclassified into vegetation coverage,non-vegetation coverage,and water bodies based on the supervision classification.The relationship between surface temperature and land cover type can be expressed as: no vegetation cover>vegetation cover>water body.The average temperature of the area without vegetation coverage is 32.79?,the average temperature of the vegetation coverage area is 28.93?,and the average temperature of the water body is 27.27?.The specific heat capacity of the water body is large,and it can absorb and store a large amount of heat radiation,and the vegetation can reduce the light for the land and reduce the heat radiation absorbed by the land.(3)The intensity level of the heat island in Changchun is divided into high temperature zone,sub-high temperature zone,medium temperature zone,sub-medium temperature zone and low temperature zone.In 2014 and 2015,the high temperature area was mainly distributed in the city center.Since 2016,the high temperature area has expanded from the downtown area.The central area of the heat island effect in each administrative area is chained by points and faces,and the core area of the high temperature area is directed towards The edge of the city is offset,and the water body and the area covered by vegetation are always kept in the low temperature zone and the sub-medium temperature zone.(4)The administrative divisions of Changchun City are Nanguan District,Chaoyang District,Kuancheng District,Erdao District and Lvyuan District.According to the changes in surface temperature and heat island intensity in each administrative region over the past five years,the green zone has the largest increase,with an average temperature rising from 27.89? to 35.87?;Nanguan District is basically the same,with an average temperature rising from 28.45? to 29.08?.Erdao District and Chaoyang District increased slightly,and the average temperature increased from27.87? to 34.63?,26.82? to 29.74?,and 30.01? to 34.03?.The relationship between the increase of heat island intensity and high temperature area and the administrative region is: Lvyuan District> Chaoyang District> Nanguan District>Kuancheng District> Erdao District.