Assessing the Heat Vulnerability of Different Local Climate Zones in the Old Areas of a Chinese Megacity

Zhi Cai,Guifeng Han,Yan Tang,Kai Chen

doi:10.3390/su11072032

Abstract

Frequent and extreme heat waves have strongly influenced the sustainable development of cities and resulted in a higher level of mortality in residents. Using the Local Climate Zone (LCZ) classification scheme, combined with the factors of land surface temperature (LST), building age (BA), and housing price (HP), and the normalized values of which represent heat exposure, sensitivity, and adaptability, respectively, this paper investigates a practical method for assessing the heat vulnerability of different LCZ classes in the old areas of a Chinese megacity, taking the Yuzhong district of Chongqing city as a case study. The results reveal that the distribution of LCZ classes in this study area exhibits a typical circle-layer distribution pattern from the city center to the suburbs. Heavy industry areas are the most vulnerable, with the highest exposure to heat waves, the oldest building age and the lowest housing price. Compact class areas (compact high-rise, compact mid-rise and compact low-rise) are usually more vulnerable than open class areas (open high-rise, open mid-rise, and open low-rise) and low-rise buildings are always more susceptible to heat waves than mid-rise and high-rise buildings. The methods and findings can help us to better understand the comprehensive and space–time action rules of heat vulnerability, thereby inspiring scientific and rational urban planning strategies to mitigate or adapt to urban heat weaves towards the sustainable development of cities and society.

Highlights

Global climate change has strongly influenced the development of sustainable cities and society and increased the intensity of extreme heat waves
To explore the acquired data to assess the urban heat vulnerability, which is suitable for Chinese mega-cities, this paper introduces three factors for modeling rapidly developing proportion of elderly people at the community level is 0.473** (p < 0.001), that is, there are more elderly people living in old communities with older housing
The results showed that the distribution of Local Climate Zone (LCZ) classes presents a typical circle-layer distribution pattern from the city center to the suburbs

Summary

Introduction

Global climate change has strongly influenced the development of sustainable cities and society and increased the intensity of extreme heat waves. Heat waves can significantly reduce the frequency of fitness activities, walking, and other outdoor activities [4], thereby increasing the risk of diseases, such as obesity, cardiovascular diseases and diabetes [5,6]. The Centers for Disease Control and Prevention (CDC) of the United States noted that the risk of symptoms, such as asphyxia, fatigue and cramps, increased significantly after frequent exposure to extremely high temperatures [7]. Rovers (2014) [12] pointed out that the number of deaths caused by heat waves in the Netherlands increased by eight people per degree, when the temperatures exceeded 20 ◦C. In 2003, an extreme heat wave caused more than 70,000 deaths in Europe [13], and the extreme heat waves in the United States from 1999 to 2010 resulted in 7415 deaths, more than the total number of deaths from typhoons, floods, earthquakes and other disasters during the same period [14]

Methods

Findings

Discussion

Conclusion