HISTORICAL SURFACE AIR TEMPERATURE TRENDS AND THE EFFECTS OF URBAN HEAT ISLAND (UHI) IN SINGAPORE AND PENINSULAR MALAYSIA

Abstract

The purpose of this study report is to examine any gradual changes to the surface air temperature in Singapore and Peninsular Malaysia and to assess the potential presence of an urban heat island (UHI) effect on the observed trend. Using surface air temperature records from 1931-2009, results of the study found that since 1950, annual mean temperature has increased by 0.36°C (0.006°C per year). Cooling in 1950-1979 (-0.015°C per year) has reduced the warming that has taken place in the earlier period (1931-1940), despite the high rate of warming in 1980-2009 (0.023°C per year). This results in the mean temperature of all stations examined in 2000-2009 (27.2°C) to be almost as warm as the mean temperature of all the stations in the first ten years of study in 1931-40 (27.0°C). On the other hand, unlike mean temperature, minimum temperature did not have a period of cooling but exhibited a period of slowed warming from 1950 to late 1970s at Malaysia stations between 1-5°N and even cooling at Malaysia stations located between 5-7°N, where temperature records are available.