A Quantitative Study On Land Use Change Trajectories And Urban Heat Island

In this paper,the Landsat series of images in 1990,1996,2011,2011 and 2016 are the main data sources in Xuzhou city area.The land use information and urbanization trajectories of five data were extracted,and the surface temperature was retrieved.The results of the inversion are divided into five heat island grades,and the area and proportion of each heat island grade of different land use types are analyzed.The influence of different land use types on heat island effect is analyzed.The absolute heat island intensity of each year is calculated and the overall change of the thermal environment in the study area is analyzed.The contribution of different urbanization trajectories to heat island effect is calculated,and the influence of different land use types on urban heat island effect in urbanization is quantified.The main findings are as follows:(1)The land use types in Xuzhou city area are dominated by two types of cultivated land and construction land.The area of cultivated land decreased year by year,while the area of construction land increased year by year.(2)The study area has been rapidly urbanized in the past 26 years,and the urban area has been expanding outward along the edge of the old city(except the southwest edge).Especially in the eastern and southeastern part of the old city,urbanization is most obviously.The expansion of the new city is mainly from the arable land from the change.(3)The spatial distribution of heat islands presents a trend of divergence to concentration.At first,the heat island in the study area was mainly distributed in the three main areas of the main city,Jiawang area and its vicinity,and the southeastern part of Tongshan District.26 years,the main city of the heat island is expanding,while the other two regions of the heat island effect has eased.(4)The absolute heat island intensity of each year(except 1996)is increasing.In general,the urban and suburban temperature difference is expanding,the urban heat island effect is significantly increased.(5)The heat island effect of different land use types is different,and the heat island effect of unused land is the most obvious,followed by construction land.The green island effect of water is the most obvious,with very good cooling effect,followed by cultivated land and woodland.(6)Different urbanization trajectories contribute differently to heat island effects.The contribution of the persistent urban trajectory to the heat island effect is decreasing year by year,while the contribution value of cultivated land ? construction land change path is growing rapidly.This shows that the process of urbanization from cultivated land to construction land plays an important role in the urban heat island effect of the study area,which weakens the influence of the persistent urban area on the heat island effect.