Analysis Of Heat Island Characteristics Of Urban Agglomeration In Yangtze River Delta Based On MODIS

In recent years, the speed of urbanization has increased. The change of the underlying surface rusults in increasing temperature difference between urban district and suburb, which leads to UHI effect. It becomes an important issue in urban sustainable development. Yangtze River Delta region is the fastest growing region in China, including cities with large economy and large population like Shanghai, Nanjing, Suzhou, and its UHI effect is particularly serious. On the other hand, RS and GIS technology has made great progress during the last few decades. Technology combining RS and GIS has become an important tool when anlaysing UHI effect. It has great significance to study the UHI effect caused by urbanization using remote sensing data.This research focused on Yangtze River Delta region, covering Shanghai, Jiangsu Province, and Zhejiang Province. Three sets of MODIS data were used incluing LST products, NDVI product, Land-Cover and Land-Use Change product. Analysing the temporal and spatial change of LST in research area from 2001 to 2013, including seasonal and inter-annual variations. Extract the pixels of UHI by mean LST in summer, and analyze the variations of sum and proportion of the UHI area in different cities in 13 years. The change of NDVI, the built-up area and ISAI was analyzed. The correlation coefficient between UHI and UHI factor was studied in the Yangtze River Delta region and different cities. The conclusions were as follows:(1) The mean LST of Yangtze River Delta area was quite closed in 13 years. The lowest mean LST appeared in 2012, while the highest mean LST appeared in 2013. The strong UHI and the greatest changed area of LST mainly distributed in southern Jiangsu, Shanghai, and Hangzhou Bay area.(2) Strong UHI mainly distributed in built-up areas. Shanghai, Hangzhou, Ningbo, and Suzhou, the industrial city, owned most UHI in urban agglomeration in summer of year 2013. Also, the sum and proportion of the strong UHI in research area were significiantly changed in 13 years.(3) The NDVI of built-up areas and water bodies was quite low and it changes a little in the seasons. The mean NDVI of the whole area was decreasing in summer. The built-up areas and ISA had significant expansion, especially Shanghai, southern Jiangsu, Hangzhou Bay area.(4) The spatial distribution of LST and NDVI, built-up areas, ISA was correlated, when focusing on the Yangtze River Delta and different cities in this area in summer of year 2001 and 2013. LST has negative correlation with NDVI, while LST has positive correlation with ISAI. The correlation coefficient between LST and ISAI is higher than the correlation coefficient between LST and NDVI.