Study On The Influence Of Land Use Characteristics On Summer Heat Island In Harbin

With the continuous development of economy and the increasing process of urbanization,the urban lower cushion has changed greatly,and the urban heat island effect is becoming more and more prominent.So that China's summer high-temperature weather,some cities continue to issue high-temperature warning,so that people feel the heat is unbearable.Through the study of the Evolution Law of urban heat island effect,it is helpful to optimize the urban human settlement environment,provide the basis for the rational planning of urban development and the relief of urban heat island effect.This paper probes into the influence of land use change on urban heat island effect and ecological environment quality in Harbin,and puts forward some mitigation countermeasures to improve the quality of urban environment.Based on the data of LANDSAT satellite remote sensing images from July-August to 2001,2008,2013 and 2017,the surface temperature in Harbin was inverted by means of radiation transmission method,density segmentation,quadrant azimuth method,buffer analysis and regression analysis,and the urban heat island effect grade was divided.This paper analyzes the general characteristics of spatial and temporal differentiation of urban heat island in Harbin,and uses four phase remote sensing images to extract land use type information and urbanization trajectory,and comprehensively and systematically analyzes the difference of urban heat island in different land use types,the relationship between ecological factors and surface temperature of the lower cushion,and the contribution of urbanization trajectory to urban heat island.The results show that:(1)The distribution of construction land in Harbin is widely distributed,and it is also the most drastic part of the transformation of land use types in various periods.The changes in the 17 were the most significant changes in construction land and cultivated land,mainly manifested in the rapid expansion of urban construction land,the decrease of cultivated land,the reduction of green space and other land,the largest reduction of arable land,the reduction of cultivated land area by 285.35 square kilometers,and the expansion range of construction land is almost consistent with the expansion range of high temperature zone.(2)The surface temperature in Harbin city is significantly higher than that of the peripheral suburbs,and presents an island-like high temperature area,the heat island phenomenon is more obvious.The Heat island area mainly focuses on the built area and industrial park in the corresponding period,while the water body,green space and cultivated land show obvious phenomenon of Cold island.(3)The expansion of the Heat island area in Harbin in 2001-2017 is obvious,but it shows different expansion direction,scope and mode in different periods,the spatial distribution of the Heat island area and the urban construction land is consistent,and the urbanization process and population flow can accelerate the expansion of the urban heat island range.(4)Through the correlation analysis of surface temperature and underlay index(NDVI/NDBI)in Harbin,it is shown that there is a negative correlation between surface temperature and NDVI,and there is a significant positive correlation between surface temperature and NDBI,and NDVI and NDBI are representative in characterizing thermal environment characteristics.(5)A total of 51 urbanization trajectory,the selection of area accounted for more than 0.5% of the trajectory of 8,in the urbanization trajectory into the construction land process,most of the transformation from cultivated land formed.The contribution of different urbanization trajectory to urban heat island is different,the contribution value of persistent urban trajectory(NO.1111)to heat island effect is the largest in 2001,and decreases year by year,but the urbanization trajectory of cultivated land into construction land continues to increase on urban heat island effect.Therefore,the urbanization process of transforming cultivated land into construction land plays an irreplaceable role in the urban heat island effect of Harbin City,which weakens the influence of the persistent old City on the heat island effect.