Study On The Effect Of Land Use Change On Land Surface Thermal Environment In The Three Gorges Reservoir Area

Land Use is one of the most basic economic activities of human beings. It is an important trend of the Land Use in recent years to study the characteristics of Land Use Change under the idea of the sustainable development. With the completion of the water storage in the Three Gorges Reservoir area and the promotion of urbanization, The Land Use Structure of the Three Gorges Reservoir area has changed significantly, the most obvious characterization is that the natural surface environment has been replaced by the city, and the rise of water level made some of the cultivated land,woodland and so on be submerged, not only to the original form and function zoning in Three Gorges Reservoir area has an important influence, but also leads to changes in surface thermal environment in the area, and produce a series of negative effects of climate, living environment, ecological and other aspects of the whole city in the Three Gorges Reservoir area.Taking the Three Gorges Reservoir Area as the research area, this study based on 2000, 2007 and 2014 three periods of Land Use data, the LST product of MODIS and vegetation cover products as the data source, Combined with remote sensing and GIS technology to analyze the impact of land use change on the surface thermal environment and the correlation between the Three Gorges Reservoir area water storage before and after. Some conclusions are as follows:(1) In the period of 2000 to 2014, the grassland, arable land, woodland and unused land area were decreased, construction land and water area were increased in the Three Gorges Reservoir area, however, the degree of land use change, land use change and land use dynamic degree are different. The comprehensive index of Land Use degree is gradually rising, it showed that nearly 14 years of Land Use Intensity increased significantly, namely the Land Use is in the development stage; The construction land,water area and cultivated land area index were more than 1, they have all obvious Location significance, in special, the head woodland, belly grassland and tail construction land have the most location significance; From different land use transfer type, cultivated land and woodland are the most vulnerable to interference types, it is mainly present the increase of cultivated land, the decrease woodland and construction land area,the increase of urban construction mainly comes from cultivated land and woodland, grassland changes was mainly present to forest and water transfer, and unused land had small changes in transfer.(2) In the period of 2000 to 2014, the Three Gorges Reservoir Area in summer the average surface temperature spatial distribution of the overall present that the West in high temperature and the East in low temperature?the tail and the belly are all in high temperature, the head and belly is in low temperature, It is mainly in the high temperature zone and warm area. The surface temperature of the Three Gorges Reservoir area reservoir head and the reservoir tail abdominal is mainly 25.29 to 31.99?, in which most of the reservoir tail surface temperature approximately at 26-32?,especially in Chongqing city and the county built-up area surface temperature up to 28.23 - 31.99?, It is mainly due to the main city of Chongqing economic development,high urbanization rate. vegetation coverage is relatively low, while the southeast temperature reservoir tail region of Jiang-jin area for a minimum of 21.93 to 23.09?, it is mainly by mountain terrain (North South high-low) effect.(3) In the period of 2000 to 2014, it has relationship between the spatial and temporal shift of the center of gravity of the reservoir head, the reservoir belly and the reservoir tail in the Three Gorges Reservoir area, and the expansion direction of the urban built-up area. Since 14 years, the gravity center coordinate of the reservoir heat island in the Three Gorges Reservoir area changes from northwest to Southeast, the gravity coordinates from the original Yi-ling District transferred to Zi-gui county and then transferred to the Yi-ling District; The center gravity of the reservoir belly is always located in Wan-zhou District, the transfer mode changed from southwest to northeast, The transfer mode of the reservoir tail changed from southwest to northeast,and the center of gravity coordinates from Yu-zhong to the South bank.(4) In the period of 2000 to 2014, the Three Gorges Reservoir Area woodland proportion was more than 50% in the strong negative heat island, strong heat island,weak negative negative heat island and non heat island, followed by arable land and grassland, the smallest proportion is construction land, namely that the cultivated land,woodland and grassland that has an important role in reducing the surface temperature mask. With the increase of heat island intensity level, the construction land area proportion increased correspondingly.(5) There are some significant differences between the different Land Use types and surface temperature in different years, the construction land surface temperature is highest, water area is lowest, construction land expansion direction and the surface temperature and heat island intensity with spatial consistency, by the county built-up area to the suburbs continue to decline; the surface temperature and the normalized difference vegetation index showed negative correlation, with the increase of NDVI value, the surface temperature is decrease, thus increasing vegetation coverage can effectively reduce the surface temperature of heat island effect.