Trend Analysis of Urban Heat Island Intensity According to Urban Area Change in Asian Mega Cities

Kyungil Lee,Seong Woo Jeon,Hyun Chan Sung,Yoonji Kim,Jieun Ryu

doi:10.3390/su12010112

Abstract

Urban heat island (UHI) is a phenomenon that occurs in cities worldwide. Therefore, there is an increasing need for studies on the changes in UHI intensity and long-term trends based on macroscopic characteristics related to urbanization. In this study, changes in seasonal UHI intensity based on urban area were analyzed for eight Asian mega cities from 1992–2012. The results indicate that the change in pattern of UHI intensity varies for different cities and seasons. UHI intensity increased as the urban area size increased. Furthermore, the dependency of UHI intensity on the economic situation was also demonstrated. With respect to the seasons, significantly increasing trends appeared during the summer. Moreover, depending on urban characteristics such as geography and climate, increasing trends appeared during other seasons. Population was also found to affect UHI intensity by generating anthropogenic heat; however, its effect as an individual factor appeared to be insignificant. This is a macroscale study that analyzes the effect of urban area size on UHI intensity. Future studies on urbanization factors and levels influencing the UHI intensity using higher resolution materials are required

Highlights

Urban heat island (UHI) is a commonly observed phenomenon worldwide; it is an urban area where temperatures are significantly higher than those in the surrounding areas
We attempted to obtain UHI intensity change trends based on urban-area size for eight Asian mega cities in different seasons using global climate modeling data
Our analysis suggests that there is a difference in the correlation between the urban-area size and UHI intensity, based on the characteristics of each city and season

Summary

Introduction

Urban heat island (UHI) is a commonly observed phenomenon worldwide; it is an urban area where temperatures are significantly higher than those in the surrounding areas It causes problems such as changes in relative humidity, increase in energy consumption, and human thermal stress [1,2,3,4]. Urban areas are the main source of anthropogenic carbon dioxide emissions, which are generated by burning fossil fuels for heating and cooling purposes, industrial processes, and transportation [6]. In this regard, the size of urban areas could be a major factor in UHI development, as explained by Oke [8]. The characteristics of such a correlation are not clearly understood

Objectives

Methods

Results

Conclusion