Impact of urbanization on land surface temperature and surface urban heat Island using optical remote sensing data: A case study of Jeju Island, Republic of Korea

Abstract

Urbanization changes the existing form of land use and cover (LULC) which can influence the land surface temperature (LST). Therefore, it is important to present the causes of urban heat island (UHI) which is usually linked with anthropogenic activities. There are very few studies on thermal behavior of Korean cities in literature. Hence, in this study we have estimated the LULC of Jeju island and analyzed LST using Landsat (TM/ETM+/OLI) images for the last two decades. The supervised image classification method employed with maximum likelihood classifier algorithm was used to classify the images and thermal band was used to calculate the LST. We have used simplified urban extent (SUE) algorithm to calculate the surface urban heat island (SUHI) and eventually we have correlated the SUHI with mean wind speed of Jeju Island. The results of LULC revealed that urban area increased from 8.69% in 2002 to 20.81% in 2021 and in this period barren land decreased by 34.88% due to urban expansion. Interestingly forest region has been slightly increased which is influenced by decreasing barren land. The accuracy was assessed using confusion matrix for the classified images and results revealed an overall accuracy of 0.87, 0.85 and 0.92 with kappa coefficient of 79.02%, 76.45% and 88.05% for the years of 2002, 2011, and 2021 respectively. The LST of all LULC classes were calculated which revealed the highest temperature for urban class which is followed by barren land. However, the forest cover and water body have the lowest temperature in the island. The intensity of surface urban heat island (SUHI) was increased from 2.47 °C (2002) to 3.10 °C (2021). We have correlated the wind speed and SUHI which revealed that SUHI and wind speed has inverse relationship. The outcome of this research can be utilized by the policymakers, urban planners, architects, and climatologist to develop policy related to climate-resilient cities.