Mitigating the scale of urban heat Island effect in cities with implementation of green roofs

Abstract

Variations of the urban heat island effect is different from city to city. To understand the variations in the heat island effect, in the center of the Colombo City the capital of Sri Lanka, with the locations of buildings and roads, the temperature and humidity was measured with the height. A detailed analysis was done to find the specific height of which the heat island effect prevails and the temperature variations with height. With that a theoretical model was developed to identify the possibilities of controlling the heat island effect. The model was developed with replacing existing flat roof areas with green roofs, in randomly selected area (0.5Km2)in the Colombo City. These findings were coupled with the energy balance in the selected area and with a computer simulation. The reduction in the temperature in the canopy air layer in the roof level was calculated. The results show that there is a variation in the heat island effect with height. When, the vertical distance increases from the heating surfaces, the heat island effect is lesser. The heat island effect can be reduced with the implementation of green roofs in the Colombo City.