Effects of Soil Moisture on Urban Heat Island Occurrences: Case of Selangor, Malaysia

Abstract: The state of Selangor experienced the most rapid development and urbanisation growth in Malaysia. In Selangor, urban encroachment was significantly found in urbanised mukims such as Kajang, Cheras and Dengkil. This article investigates the application of remote sensing thermal infra red band for detecting land surface temperature and the effect of soil moisture content on urban heat island occurrences. A subset of Landsat TM acquired on April 17th, 1988 and February 11th, 1999 that covers Kajang-Cheras-Dengkil area (with less than 5 percent cloud cover on the image) were used in this study. The 1999 image was used in this study due to substantial changes in land use and land cover within the new administrative centre, i.e. Putrajaya. The image interpretation result showed the increase of urban cover within the period, from 69330 ha in 1988 to 91420 ha in 1999. Even though the urban cover increased within the period, the heat island phenomenon was less occurred in 1999. A further analysis showed the antecedent precipitation index prior to the scene acquisition for February 11th 1999 was comparatively very high and produced high value of soil moisture content. It is believed that the high moisture content due to antecedent precipitation in 1999 image has a removal effect on the urban heat island intensity. Key words: Urban heat island · urban cover · soil wetness · antecedent precipitation inde