PROGRESS IN GEOGRAPHY ›› 2019, Vol. 38 ›› Issue (12): 1944-1956.

• Articles •

### Spatial variability of urban thermal environment based on natural blocks

YANG Zhiwei1,2, CHEN Yingbiao1,2,*(), WU Zhifeng1,2, QIAN Qinglan1, HUANG Qingyao1

1. 1. School of Geographical Sciences, Guangzhou University, Guangzhou 510006, China
2. Guangdong Province Engineering Technology Research Centre for Geographical Conditions Monitoring and Comprehensive Analysis, Guangzhou 510006, China
• Received:2019-02-18 Revised:2019-03-11 Online:2019-12-28 Published:2019-12-28
• Contact: CHEN Yingbiao E-mail:gzhuchenyb@126.com
• Supported by:
Natural Science Foundation of Guangdong Province(2016A030313551);National Natural Science Foundation of China(41671430);National Natural Science Foundation of China(41771127)

Abstract:

Addressing the issue of subdivision of construction land for quantitative evaluation of spatial variability of urban thermal environment is of great significance for improving the ecological environment of cities and realizing the healthy development of urban areas. In this study, we used Landsat 8 remote sensing imageries to retrieve the surface temperature data of Guangzhou City. Based on the concept of natural city combined with the classification standard of urban construction land, we identified five types of natural blocks based on the open data of point of interest (POI). On this basis, the distribution pattern of land surface heat field levels, thermal field average value of natural blocks, and thermal environment footprint range were calculated and analyzed to evaluate the spatial variability of the urban thermal environment of the city. The results show that: 1) The identification of natural blocks may accurately reflect the spatial distribution of all kinds of POI and realize a meaningful division of the sub-types of construction land. 2) Land surface heat field in the five types of natural blocks was dominated by high temperature pixels (more than 90%), and the distribution range of low temperature pixels is small (less than 1%). But the distribution of the heat field levels was significantly different across the natural blocks. In the residential, road and traffic, and public management and service natural blocks, the proportion of land surface heat field levels was similar; the proportion of mesothermal pixels in the commercial and services natural block was less than half of the above three types of natural blocks. The proportion of high temperature pixels in the industrial natural block was the highest, reaching 99%, and there was no low temperature pixel. The order of thermal field average value of natural blocks from high to low is: industrial natural block > commercial and services natural block > road and traffic natural block > residential natural block > public management and service natural block. 3) Heat diffusion exists in the high temperature agglomeration area formed by natural blocks, and the actual influence range is larger than its physical boundary. The thermal environment footprint range of the five types of natural blocks was different. The thermal environment footprint of industrial natural block was the widest, and the 6th ring buffer zone was still in the scope of impact. While the thermal environment footprint of public management and service natural block only affects the 2nd ring buffer zone, compared with the other four types of natural blocks, the effect of heat diffusion was not significant. The influence range of thermal environment footprint from large to small is: industrial natural block > commercial and services natural block > residential natural block > road and traffic natural block > public management and service natural block. The result of this study may provide some scientific basis for the analysis of urban thermal environment, the improvement of urban ecological environment, and the healthy development of urbanization.