The Effects of Vegetation Growth on the Microclimate of Urban Area: A Case Study of Petaling District

It is well known that the surface temperature distribution in the urban area is significantly warmer than its surrounding suburban areas. This phenomenon is known as urban heat island (UHI). Vegetations play a vital role to mitigate the UHI effects especially in regulating high temperature in saturated urban area. This study attempts to assess the effect of vegetation growth on the surface temperature distribution of the surrounding areas. The area of study for this research is Petaling District (i.e. City of Shah Alam, Petaling Jaya and Subang Jaya), Selangor. To monitor the land use/land cover changes within the study areas, Landsat 5 TM images of 1991 and 2009 are used. The land use/land cover of the study area is classified into five major classes i.e. water bodies, high-dense trees, mix-vegetation, built-up area and open land. Based on the thermal band of Landsat 5 TM, the land surface temperature maps are derived. Mono-window algorithm is used to convert digital number to surface temperature. Results from this study have shown that there are significant land use changes within the study area. This study demonstrates that rapid urban growth significantly decreased the vegetated area, hence increased the surface radiant temperature. Although the conversion of green areas to residential and commercial areas significantly increases the land surface temperature (LST), matured trees help to mitigate the effects of UHI.