Empirical study on temporal variations of canopy-level Urban Heat Island effect in the tropical city of Greater Kuala Lumpur

A very few studies have evaluated and understood the temporal dynamics of UHI in many expanding tropical cities. Hence, this study investigated the temporal variations of canopy-level UHI in selected urban stations, namely Petaling Jaya (PJ) and Subang (SUB), of Greater Kuala Lumpur (GKL) using 2016’s hourly data set obtained from meteorological observatories. The association between meteorological factors and UHI Intensity (UHII) is evaluated using linear regression models and Pearson correlation analysis. The findings revealed positive thermal contrasts between urban and sub-urban stations with maximum UHII during dry, southwest monsoon season in PJ (June: 1.68 °C) and SUB (August: 1.29 °C) stations respectively. PJ station exhibited a distinct diurnal cycle with the maximum nocturnal UHII of 1.71 °C at about 8 p.m. after sunset under ideal meteorological conditions. The results also demonstrated that UHI events occurred more frequently at nights in urban stations in the magnitude range of 0–2 °C. Cooling at all urban sites starts around 2–3 p.m. with the highest rate of 0.73 °C/h and 0.96 °C/h in PJ and SUB stations. Meanwhile, relative humidity displayed a low positive correlation (r = 0.37, p ≥ 0.05) and a high negative correlation (r = −0.79, p < 0.05) with UHII in PJ and SUB stations respectively. The influence of wind speed on UHII is weak (r = −0.44, p < 0.05) in PJ station and strong (r = 0.83, p < 0.05) in SUB station. Overall, this study can be regarded as one of the comprehensive observational investigations of canopy-level UHI in a tropical city that provide vital inputs to enrich the tropical urban climate literacy

A qualitative exploration on the awareness and knowledge of stakeholders towards Urban Heat Island phenomenon in Greater Kuala Lumpur: Critical insights for urban policy implications

Despite its notable role in the exacerbation of urban climate, Urban Heat Island (UHI) was poorly addressed, communicated and integrated into local urban policies of many developing countries. Such scenario often queried the level of UHI understanding amongst the key players who were involved in urban policy formulation. Hence, a qualitative study using Focus Group Discussions (FGD) was designed to investigate the awareness and knowledge level of stakeholders such as policy makers and practitioners in Greater Kuala Lumpur (GKL), an expanding socio-economic hub of a developing tropical country. The findings demonstrated a variable lack of awareness and knowledge about the concept of UHI, its status in GKL as well as organizational engagement in adaptation and mitigation initiatives among the study participants. Essentially, policy makers illustrated a facile awareness and knowledge towards UHI issues whereas practitioners displayed a more robust portfolio of factual understanding regarding the corresponding issues. In line with National Urbanization Policy's (NUP) aspiration to optimize urban developments that provide high quality of life, this study sheds some light on the exigency for UHI awareness creation and capacity building among the policy makers. This study also provides impactful prepositions for the articulation of necessary actions towards evidence-based urban policy formulation in future. © 201