Water bodies as a stable reference for urban heat islands intensity measurements

Abstract

Accurate measurement of urban heat islands (UHI) intensity is a necessary prerequisite for understanding UHI formation mechanisms and subsequently implementing effective prevention and control measures. The selection of a stable reference is a significant challenge in this process. In particular, rapid urbanization can lead to changes in land cover types. This process hinders the selection of a typical non-urban area as a stable reference for accurately measuring surface urban heat islands (SUHI) intensity. Among various land cover types, water bodies are widely distributed and stable during urban development. Nevertheless, the use of water bodies as a stable reference for SUHIs remains controversial. For 185 global cities, we first clustered the land cover transformation rates and then compared the interannual variations in SUHIW and SUHIR in these cities by using remote sensing data from MODIS. The trends of interannual intensities of the SUHIW and SUHIR in the stable group are similar, indicating that water bodies have the same effect on SUHI measurements as stable rural areas. However, the magnitude of the difference between the SUHIW and the SUHIR (SD) becomes more significant in cities with rapid changes in rural areas. As a stable reference, water bodies can be used to accurately measure the variation in the SUHI affected only by urbanization under the background climate, while the land cover transformation of rural areas changes the land surface temperature (LST) and thus affects the SUHI intensity. The findings of this study quantitatively demonstrate the feasibility of using water bodies as SUHI references from an urban dynamics perspective and provide direction for studying SUHIs under climate change.

Keywords

• Surface urban heat islands
• Water bodies
• Remote sensing