Urban Heat Island Analysis Using the Landsat TM Data and ASTER Data: A Case Study in Hong Kong

TLDR

The study analyzes Hong Kong’s urban heat island effect using 2005 Landsat TM and ASTER satellite data. Two algorithms were used to derive land surface temperature maps from Landsat TM and ASTER, and the resulting LST was correlated with NDVI and NDBI to assess green and built‑up land impacts. Urban heat islands in Hong Kong are concentrated in Kowloon Island, northern Hong Kong Island, and the International Airport, with LST negatively correlated with NDVI and positively with NDBI, indicating green land mitigates while built‑up land amplifies the effect; satellite‑derived LST maps are useful but require in‑situ validation.

Abstract

In this paper, the effect of urban heat island is analyzed using the Landsat TM data and ASTER data in 2005 as a case study in Hong Kong. Two algorithms were applied to retrieve the land surface temperature (LST) distribution from the Landsat TM and ASTER data. The spatial pattern of LST in the study area is retrieved to characterize their local effects on urban heat island. In addition, the correlation between LST and the normalized difference vegetation index (NDVI), the normalized difference build-up index (NDBI) is analyzed to explore the impacts of the green land and the build-up land on the urban heat island by calculating the ecological evaluation index of sub-urban areas. The results indicate that the effect of urban heat island in Hong Kong is mainly located in three sub-urban areas, namely, Kowloon Island, the northern Hong Kong Island and Hong Kong International Airport. The correlation between LST and NDVI, NDBI also indicates that the negative correlation of LST and NDVI suggests that the green land can weaken the effect on urban heat island, while the positive correlation between LST and NDBI means that the built-up land can strengthen the effect of urban heat island in our case study. Although satellite data (e.g., Landsat TM and ASTER thermal bands data) can be applied to examine the distribution of urban heat islands in places such as Hong Kong, the method still needs to be refined with in situ measurements of LST in future studies.