Assessment of influence of reflective roofs on reducing urban heat island effect by satellite images(A case study in Kermanshah)

As urban areas develop، changes occur in the landscape. Buildings، roads، and other infrastructure replace open land and vegetation. This development leads to the formation of urban heat islands، whereby urban regions experience warmer temperatures than their rural surroundings. The temperature changes decrease the quality of urban life، especially in matters relating to thermal comfort. Where as most urban surfaces formed from rooftops، streets and sidewalks، considering these surfaces، can be effective in reducing the urban heat island effect. The aim of this study was to evaluate the role of reflective roofs in reducing the urban heat island effect. In this study، using multitemporal images of Landsat TM، the impact of reflective roof (tar paper with Coating Aluminum foil) on changes in reflection، absorption and surface temperatures in Kermanshah city، between 1987 and 2011 were examined. To obtain the land surface temperature used the Qin ET all’s single-band algorithm. Results Statistical analysis showed that the reflectance in the period under study had an average 8% increase and this increase reflects increased a cooler temperature class’s area that distributed over of residential buildings. This is while with the development of the city and declining vegetation within the city and surrounding Gharehsou River، there has been a reduction the very cool temperatures area and Very warm temperatures have increased floor area. The spatial variation of the reflect and surface temperature during the study period showed that in areas that reflect the increased surface temperature was associated with a decrease and The use of reflective roof to reduce heat island effect can be effective.