Quantitative Analysis of a Spatial Distribution and Driving Factors of the Urban Heat Island Effect: A Case Study of Fuzhou Central Area, China.

Meizi You,Jiayuan Lin,Zhesheng Zhu,Riwen Lai

doi:10.3390/ijerph182413088

Abstract

Land surface temperature (LST) is a joint product of physical geography and socio-economics. It is important to clarify the spatial heterogeneity and binding factors of the LST for mitigating the surface heat island effect (SUHI). In this study, the spatial pattern of UHI in Fuzhou central area, China, was elucidated by Moran’s I and hot-spot analysis. In addition, the study divided the drivers into two categories, including physical geographic factors (soil wetness, soil brightness, normalized difference vegetation index (NDVI) and modified normalized difference water index (MNDWI), water density, and vegetation density) and socio-economic factors (normalized difference built-up index (NDBI), population density, road density, nighttime light, park density). The influence analysis of single factor on LST and the factor interaction analysis were conducted via Geodetector software. The results indicated that the LST presented a gradient layer structure with high temperature in the southeast and low temperature in the northwest, which had a significant spatial association with industry zones. Especially, LST was spatially repulsive to urban green space and water body. Furthermore, the four factors with the greatest influence (q-Value) on LST were soil moisture (influence = 0.792) > NDBI (influence = 0.732) > MNDWI (influence = 0.618) > NDVI (influence = 0.604). The superposition explanation degree (influence (Xi ∩ Xj)) is stronger than the independent explanation degree (influence (Xi)). The highest and the lowest interaction existed in ”soil wetness ∩ MNDWI” (influence = 0.864) and “nighttime light ∩ population density” (influence = 0.273), respectively. The spatial distribution of SUHI and its driving mechanism were also demonstrated, providing theoretical guidance for urban planners to build thermal environment friendly cities.

Highlights

Influenced by urbanization and industrialization, the global surface ecological structure saw great and profound changes in the past century [1]
This study focuses on the surface layer heat islands (SLHI) which attracts more and more attention and all urban heat island (UHI) mentioned below refer to surface heat islands, unless otherwise noted
The large standard deviation of Gi∗ within the circles indicates that the UHI effect varies widely in different directions, in line with the trend of the city developing to the south and east

Summary

Introduction

Influenced by urbanization and industrialization, the global surface ecological structure saw great and profound changes in the past century [1]. The dramatic expansion of urban built-up areas leads to changes in surface characteristics and increases the storage of urban surface energy [2]. The perspective of urban population expansion is pessimistic, with 58% of the world’s population expected to live in cities by 2050 (World urbanization prospects, 2018) [3]. Of particular concern is that fact that 67~76% of global energy and 71~76% of CO2 emissions of global ultimate energy are consumed in city systems [4]. Greenhouse gas emissions promote global warming and cause strong thermal discomfort and inconvenience to the urban population, which increases the energy demand for artificial indoor air cooling [5,6]. A vicious circle of energy consumption and generation is built [7]

Methods

Discussion

Conclusion