The Impact of Land Cover Changes on Land Surface Temperature in Klang Valley, Malaysia

Abstract

The Klang Valley and its suburbs have grown rapidly as a metropolitan city since the 1990s with various infrastructure areas for commercial, residential, transportation, industry, and other purposes. Urban expansion has led to widespread land use changes due to demand from population growth and economic activity. The reduction of green space has affected the Land Surface Temperature (LST) by unbalancing the surface energy budget. Higher LST in urban areas reduces the comfort of urban residents resulting in increased use of air conditioners. This will affect the ozone layer and in turn, contribute to global warming. In this study, Landsat 8 data for the years 2014 and 2021 over Klang Valley area (Kuala Lumpur, Petaling, and Putrajaya districts) were used to obtain the land cover map, vegetation indices, and LST for the land cover change analysis with temperature. The aim of this study are to examine urban land cover change and its impact on urban temperature and study the relationship between LST and vegetation indices such as NDVI (Normalized Difference Vegetation Index), MNDWI (Modified Normalized Difference Water Index) and NDBI (Normalized Difference Built-up Index) for all three (3) districts. Results show that LST values have a negative correlation with NDVI and MNDWI for all three (3) districts for two (2) different years. Whereas, NDBI had a positive correlation with LST.  Our further analysis focused on urban class temperatures, where it revealed that LST did not show any significant increase from 2014 to 2021 due to the urban expansion rate of about 3%.  The temperature of KL and Petaling is slightly higher than Putrajaya due to urban size which is more than 80% for KL and 70% for Petaling compared to Putrajaya of only 50%.  Mean urban temperature shows that Putrajaya has the lowest temperature compared to Kuala Lumpur and Petaling district, due to urban percentage of only 50% and the rest consists of greenery and water area. KL green areas with only 17% left and Petaling area with 25% in 2021, are among the factors for increasing temperature. Areas with no vegetation and are covered with impervious surfaces cause a temperature rise. Warmer places mostly consist of impervious surfaces, while those with vegetation cover are associated with lower temperatures. It is noteworthy that the Golden Triangle area in Kuala Lumpur has a lower LST in 2021. This is due to shadows from high-rise buildings affecting the LST values.