Abstract
As the population in urban areas around the world grows each year, cities struggling to cope with the increased urban migration expand at varying rates. This urban sprawl comes with the expansion and exacerbation of the Surface Urban Heat Islands (SUHI) of cities. The connection between land-use/land-cover (LULC) and the Land Surface Temperature (LST) is the focus of this study, more specifically which of the LULC practices prevalent in Pakistani cities are particularly contributing to the formation, expansion and intensification of SUHIs is the question this study aims to answer. LST of the district of Lahore was calculated using Landsat images more than a decade apart. The LULC types were also mapped using supervised classification techniques, while the training areas for the classification were gathered using random sampling technique during a survey of the study area. Using the resultant LST & LULC maps of the city and superimposing the boundaries of several new satellite towns of the city, the temporal changes in LST and LULC were compared. The built-up surface area within the city district in 2011 showed 25% increase since 2000, this caused the SUHI to expand as well. Previous studies pertaining to the issue of LST in Pakistani cities have shown the fact that with the growth of the cities the SUHIs have also grown, this study goes a step further and identifies the specific land use activities and land cover types that have contributed to the expansion as well as intensification of the SUHI. Among the identified LULC classes, the Sand/Vacant land class consistently turned out to the warmest of LULCs found in the study area. Further focus on individual neighborhoods of the city show that the rise and fall of the Sand/Vacant Land LULC type also accompanies the rise and fall of the average LST of the area. The average LST of the entire target district showed a rise of 0.73 ℃ in 2011. The study concludes that the ever increasing encroachment of the city’s newly developed suburbs over the countryside have accompanied an overall warming of the district’s average LST over the past decade and that letting the land lie vacant for years after clearing the agricultural fields for future urban development is a practice that has undesirable environmental effects. Adding more environmental factors and increasing the temporal span of the study would help ascertain a causal relationship between UHI and LULC practices.