Surface Urban Heat Island Formation in Colombo District: Strategic Solutions

Abstract

Climate change and unplanned urban development increase the temperatures of urban areas compared to rural areas. It is important to figure out which land use categories have made an impact on Surface Urban Heat Island (SUHI) formation. This is a major eco-environmental issue directly influencing people’s health and wellbeing and most importantly, the city’s energy use. Over the years, the temperature of urban areas in the Colombo district has increased. This study aims to observe the relationship between SUHI formation in the study area and the change in land cover from 2013 to 2020. The Landsat 8 OLI data are used to classify land cover and Landsat 8 TIRS data is used for surface heat profiling and classification using Urban Thermal Field Variance Index (UTFVI). Impervious Surfaces (IS) cover shows an increasing trend, water bodies show a decreasing trend, and bare lands show a fluctuation throughout the study period. The mean temperature in the Colombo district has increased from 24°C to 27°C from 2013 to 2020. The impact of changes on IS, Green Space 1 (GS1), and Green Space 2 (GS2) are correlated with the increase in Land Surface Temperature (LST). The increasing trend of IS cover is directly linked with the decreasing trend in the GS1 and increasing trend of GS2. The influence of the landscape components is important for SUHI formation. Therefore, findings from this study help the policymakers to take necessary actions for the health and wellbeing of the city dwellers to drive the country towards strategic solutions for sustainable development.