Study On Spatial-Temporal Distribution And Causes Of Heat Island Effect In Yangtze River Delta Based On Modis

With the rapid development of RS and information technology represented with"3S",using RS and GIS technology to monitoring the urban heat field information quickly and efficiently and studying the trend of UHI expansion and the time-space distribution characteristics is significant for optimizing the urban ecology environment and guiding the urban planning.Land surface temperature (LST)is an important factor of the urban heat research. With the in-depth study of urban thermal environment, how to monitoring and calculating LST is more and more important. Supported by RS and GIS, the paper selected the Yangtze River Delta as representative area to studying the inversion of LST by remote sensing image of MODIS from 2001 to 2008, which is in a rapid development of urbanization. By the inversion theory, the paper studied distributional characteristics and Variations of Urban Heat Island, then the mechanisms of UHI variation are also explored.The main results are as follows:(1)All the 16 cities are heat centers, all regions show the word of "Z" heating-island region distribution pattern and Hang Zhou, Shanghai as the turning points. (2)The features of UHI in summer is the strongest in Yangtze River Delta, spring is the next. In autumn and winter, most regions were in weak UHI, the features of UHI in Zhou Shan are not very obviously. by studying UHI in the spring from 2001 to 2008,it is found that the strength of UHI in 2002 is the smallest. with the process of urbanization, the area of strongest UHI was also increase and fall in 2006.in all the regions in Yangtze River Delta, shanghai is always the biggest strong UHI area. (3)The paper study the cause analysis by using land use map,the urban expanded area and NDVI layout map from 2001 to 2008 and come to a conclusion that the expand of urban is the direct reason, NDVI can reflect the strength of HUI to a certain extent. (4)As a typical area of shanghai,Quantitative Analysis are used in the relation of URI and density of population,relation between URI and percentage of greenery coverage, the UHI crowding level and the wind speed.