Study On The Temperature Characteristics Of Chengdu Based On Multi-sourse Remote Sensing Data

With continuous urban expansion and population centralization,affected by multiple action of the global warming and regional warming,in a number of large cities the extreme high temperature occurs frequently,and the urban heat island and atmospheric environmental pollution intensifies.A series of consequent problems like energy shortage,surface environment destruction,and urban heat island phenomena and so on,has seriously obstructed the positive ecological development of the city.To solve the problem,this thesis takes Chengdu city which has a high urbanization level as an example,using Landsat data and MODIS temperature data as the main data source,and under the support of remote sensing quantitative retrieval and GIS spatial analysis technology,firstly according to MODIS temperature data analyzes the characteristics of the surface temperature of Chengdu city from regional scale.And then on this basis the thesis predominantly studies the Beltway areas having abnormal surface temperature,making use of Landsat TM/OLI data and employing thermal radiation equation method to inverse the surface temperature of these areas;through Mean-Standard Deviation classification of the reversion results,overlaying the main ring roads with administrative districts,and combined with ArcGIS spatial analysis and its statistical techniques,it studies the temporal and spatial distribution characteristics and the trend of change of surface temperature;further in combination with in-depth analysis of the relevant city planning data it finds out the main driving force leading to variation of soil temperature,and proposes the corresponding update strategies for urban planning.The main achievements of this thesis are as follows:(1)Take the MODIS geothermal products as data source,study found that Chengdu's high surface temperature zones generally were relatively centralized in different periods and the most predominant area was within the beltway which had an obvious urban heat island phenomenon during 2000-2013.(2)Retrieving the surface temperature of key research areas using Landsat data,study found that the high surface temperature zone of the beltway area of Chengdu was comparatively concentrated and the phenomenon of urban heat island was obvious which is consistent with the analysis result of MODIS ground temperature data during 2000-2013.(3)In the light of the classification results of the surface temperature and the statistical data,the spatial distribution characteristics of the surface temperature has been analyzed,and the research findings are:(1)in 2000 within the research region,areas having heat island mainly distributed in Wuhou District,Chenghua District and Jinjiang District between the 2nd ring and 3rd ring road,and middle temperature zones primarily distributed in the southeast while the low temperature zones were mainly in the northwest;during 2005-2013 heat island zones predominantly distributed in Wuhou District,Chenghua District and Jinniu District between the 2nd ring road and beltway,middle temperature zones primarily distributed in vast majority of areas except the southeast while the low temperature zones were mainly in the annular region between the 3rd ring road and beltway;(2)From 2000 to 2013,the heat island phenomenon in the study area decreased first and then increased,presenting a trend of continuous outward shift from the center,and the shifting trend was from fast to slow;the middle and low temperature zones both showed an overall transfer phenomenon,and were in opposite directions.(4)Through the correlation analysis between the surface temperature and seven indicators in relation to urbanization(vegetation,water,building density,city road network,population,and GDP),the study finds out that:the change of surface temperature is correlative with vegetation,water,building density,city road network,population density,and GDP,and the ability of these six indicators to influence the surface temperature are different during different periods;the vegetation,water and construction density comparatively contributes greater to the change of the surface temperature,of which,the vegetation and water have a negative correlation with surface temperature and they can lower the surface temperature,while building density,population density and other factors show a positive correlation with surface temperature.(5)According to analysis result of the affecting factors of the change of surface temperature,this thesis proposes some advises for urban planning to alleviate the urban heat island effect:(1)building low carbon city:optimizing the industrial layout,should be arranged along the north east direction;constructing diversified energy supply system;developing circular economy industry;reducing the traffic demand.(2)constructing sponge City:paying attention to the protection of city vegetation and water;increasing area of city greening and water;constructing composite green structure;promoting eco permeable pavement;painting building insulation reflective materials.