Documenting the evolution and expansion of surface urban heat in the Bangkok Metropolitan Region, 2000–2019

ABSTRACT The evolution of land surface temperatures (LSTs) within the Bangkok Metropolitan Region (BMR) is examined with respect to patterns of urbanization from 2000 to 2019. Change detection as well as examinations of five periods within the 20 years yield insights into the spatial patterning of surface urban heat (SUH) within the BMR. Results suggest that the LSTs in portions of the BMR have increased more than 5°C during the 20-year period. The spatial distribution of SUH exhibits a pattern where high LSTs occur outward and primarily westward from the urban core along highways serving as development corridors and related regions of rapid urbanization. Nighttime LSTs have not increased as markedly as daytime; however, several noted “hotspots” have intensified over time and are located in districts along the southern seaboard. The greatest LST increase through the 20-year period is located in the northwest of the Bangkok urban core in Bang Kruai and Mueang Nonthaburi. A close investigation of this area indicates that the LST hotspots are co-located with rapid urban expansion into the area that has been facilitated by the destruction of orchards and other agriculture lands from a flood that occurred in 2011. The significant changes in land cover from orchards and agriculture to urban and built-up have led to the large increases in LSTs within the region.