DECADES CHANGE AND MECHANISM OF THE URBAN HEAT ISLAND EFFECT IN WUHAN BASED ON RS AND GIS

In order to reveal the urban heat island effect in Wuhan which is well-known asstove,urban heat island intensity,vegetation fraction,land use type and the city zone area were retrieved and computed using 3periods(1987,1994,2005)of TM image data with the support of GIS(geographical information system).Based on the standard processing of the obviously different heat island intensity data in 3periods,the present situation and evolvement of urban heat island effect in Wuhan were analyzed,the correlation of urban heat island intensity with land use type and vegetation fraction was also quantificationally analyzed.The result indicates that urban heat island effect in Wuhan is very obvious,especially in the industrial park and shopping centre.Since 1980s,the area of Wuhan heat island continuously expands.There is a negative correlation between urban heat island intensity and vegetation fraction,and the growth of 10% in the vegetation fraction will bring about nearly 1.1℃decline in the heat island intensity.Contributions to heat island of different land use type are varied.Water body and vegetation could ease urban heat island effect,while industrial park,shopping centre and road could aggravate heat island effect.Increase of city zone area,decrease of water area and drop of vegetation fraction could result in the aggravation of Wuhan urban heat island effect.