Assessment of Urban Heat Island (UHI) using Remote Sensing and GIS
This study assesses the Urban Heat Island (UHI) effect and evaluates the impact of urban/suburban areas in Lahore District on its land surface temperature using Remote Sensing and GIS techniques. The satellite brightness temperature information derived from the medium resolution satellite LANDSAT 5 (Thematic Mapper) is analyzed and compared with the land use/land cover types acquired by classifying the image. The results reveal that urban heat island in Lahore District is significant, with average Land surface temperature values ranging from 23ºC to 44ºC, and maximum urban/non-urban temperature difference reaching 5ºC. The high built-up area exhibits the maximum surface temperature ranges from 31 to 44ºC compared to other land use types. The relationship between thermal behavior and NDVI is also analyzed and negative correlation is identified by the results from the extracted surface temperature and NDVI from Landsat. This suggests that vegetation is the primary determinant controlling the spatial distribution of land surface heat. An effort to compare the population density and air pollution parameters with surface temperature is also made and the air pollution concentration is considered in relation with urban areas of high temperature and high population density.
