Climate change-induced urban heat Island trend projection and land surface temperature: A case study of Thailand?s Bangkok metropolitan

This research projects future climate change-induced urban heat island (UHI) trends (2022-2099) using three dynamically downscaled regional climate models (RCM1 - RCM3) under two repre-sentative concentration pathways: RCP4.5 and 8.5. RCP 4.5 is a moderate scenario in which emissions peak around 2040 and then decline, while RCP 8.5 is the highest baseline emissions scenario in which emissions continue to rise throughout the twenty-first century. An RCM is a numerical climate prediction model forced by specified lateral and ocean conditions from observation-based dataset that simulates atmospheric and land surface processes. In the study, the RCMs are based on three respective global climate models: ICHEC-EC-EARTH, MPI-M-MPI-ESM-MR and NOAA-GFDL-GFDL-ESM2M. The study area is Thailand's capital Bangkok, and the UHI trends are determined by the Mann-Kendall trends and Sen's slope estimates of 13 future temperature-based extreme climate indexes, consisting of nine warm extreme indexes and four cold extreme indexes. The findings reveal that the majority of the warm extreme indexes are trending upward, while most of the cold indexes exhibit a downward trend. In essence, the Bangkok metropolitan area highly likely experiences warmer temperatures in the future, contributing to higher land surface temperature and UHI intensity.