Effect of Urban Growth on Land Surface Temperature and Mitigation Strategies: A Case Study of Kathmandu Valley

The rapid increase in urban population has intensified the demand for infrastructure, resulting in the conversion of natural surfaces, particularly vegetation, into built-up areas. Such non-vegetated surfaces absorb and store more heat, contributing to higher land surface temperatures. This change in land cover is seen to increase the land surface temperature. Kathmandu has experienced rapid urban growth over the past few decades. Recently, Kathmandu has been identified as being on the verge of climate change, especially in the context of urban warming. This study has incorporated remotely sensed Landsat data, utilizing remote sensing techniques, to effectively quantify the spatial extent of urban growth and its impact on land surface temperature in Kathmandu Valley, Nepal. In this research, we employed supervised classification and change detection to identify the spatial trends of land-use and land-cover change. After that, we obtained the spatial pattern of LST using the thermal band of Landsat images. Based on our analysis, we found that the urban area increased by 13% during the period from 2013 to 2019. The surface temperatures were greater for bare soil and urban land use types. The land surface temperature ranges obtained were -3.270°C to 36.460°C in 2013, -1.910°C to 27.030°C in 2016, and 13.260°C to 40.840°C in 2019. To mitigate urban warming, strategies such as expanding urban forestry, adopting reflective building materials, and promoting sustainable urban planning are recommended for Kathmandu Valley.