Land Use Land Cover Change and Urban Heat Island in Kathmandu Valley

Abstract

The growth of urban areas has significant impact on land use/cover by replacing areas of vegetation with residential and commercial areas and their related infrastructure. This brings fluctuation in weather and climate at local scale, generally escalates the land surface temperature (LST). Significant increase in temperature due to human activities in urban areas than its surrounding is known as Urban Heat Island (UHI), which is reflected by increased Land Surface Temperature. Rapid urban growth has occurred in Kathmandu Valley due to enhanced political and economic growth in last few decades. This study aims to examine the effect of land use/cover changes on LST. Landsat images (Landsat 7-ETM+ and Landsat OLI_TIRS-8) of 2005 and 2019 were used for analysis. Land use/cover categories were classified using supervised classification by taking several samples of pixels and to generate the land surface temperature (LST) thermal bands were used. Different indices, normalized difference vegetation index (NDVI), normalized difference built-up index (NDBI), normalized difference bareness index (NDBaI) and normalized difference water index (NDWI) were also computed and used in classification of study area. The relationship between LST with NDVI and NDBI was analyzed using linear regression using Saga GIS. The study results reveal that the changes in land use/cover have a significant role in the acceleration of LST. The highest temperatures are associated with built-up areas, ranging from 27°C and 31°C while lower temperatures are related to forests, ranging from 15°C to 22°C, respectively, in 2005 and 2019. This study also proves that NDVI correlate negatively with LST while NDBI correlate positively; indicating the change in land use/cover from forest to urban increases the LST.