How Do Two- and Three-Dimensional Urban Structures Impact Seasonal Land Surface Temperatures at Various Spatial Scales? A Case Study for the Northern Part of Brooklyn, New York, USA

Wen He,Mingyi Du,Yuee Cao,Shisong Cao,Jianghong Zhao,You Mo,Deyong Hu,Manqing Liu

doi:10.3390/rs13163283

Abstract

Identifying the driving factors of urban land surface temperatures (U-LSTs) is critical in improving urban thermal environments and in supporting the sustainable development of cities. Previous studies have demonstrated that two- and three-dimensional (2D and 3D) urban structure parameters (USPs) largely influence seasonal U-LSTs. However, the effects of 2D and 3D USPs on seasonal U-LSTs at different spatial scales still await a general explanation. In this study, we used very-high-resolution remotely sensed data to investigate how 2D and 3D USPs impact seasonal U-LSTs at different spatial scales (including pixel and city block scales). In addition, the influences of various functional zones on U-LSTs were analyzed. The results show that, (1) generally, the links between USPs and U-LSTs at the city block scale were more obvious than those at the pixel scale, e.g., the Pearson correlation coefficient (r) between U-LST and the mean building height at the city block scale (summer: r = −0.156) was higher than that at the pixel scale (summer: r = −0.081). Tree percentage yielded a considerable cooling effect on summer U-LSTs on both the pixel (r = −0.199) and city block (r = −0.369) scales, and the effect was more obvious in regions with tall trees. (2) The independently total explained variances (R2) of 3D USPs on seasonal U-LSTs were considerably higher than those of 2D USPs in most urban functional zones (UFZs), suggesting the distinctive roles of 3D USPs in U-LST regulation at the local scale. Three-dimensional USPs (R2 value = 0.66) yielded more decisive influences on summer U-LSTs than 2D USPs did (R2 value = 0.48). (3) Manufacturing zones yielded the highest U-LST, followed by residential and commercial zones. Notably, it is found that the explained variances of the total study area for seasonal U-LSTs were significantly lower than those of each UFZ, suggesting the different roles of 2D and 3D USPs played in various UFZs and that it is critical to explain U-LST variations by using UFZs.

Highlights

Urbanization creates a well-known phenomenon called urban heat island (UHI, acronyms used throughout the manuscript are listed in Appendix A, Table A1)
Given that the highest urban land surface temperatures (U-land surface temperature (LST)) often appears during summer daytime [25], we investigated U-LSTs in different urban functional zones (UFZs) in summer
It is found that the explained variances of the total study area for seasonal U-LSTs were significantly lower than those of each UFZ, suggesting that different roles of 2D and 3D urban structure parameters (USPs) played in various UFZs, and it is critical to explain

Summary

Introduction

Urbanization creates a well-known phenomenon called urban heat island (UHI, acronyms used throughout the manuscript are listed in Appendix A, Table A1). This phenomenon refers to urban regions experiencing higher temperatures than their surrounding rural areas [1]. UHI effects negatively impact eco-environments and people’s. 2021, 13, 3283 health, such as air pollution, energy consumption, and greenhouse gas emissions. These impacts can be exacerbated during summer heatwaves [2,3,4]. The United Nations points out that, by 2050, the urban population will reach 66% in the world [5], which means more people will be exposed to heatwaves. Mitigating UHIs becomes a significant challenge to achieve global sustainable development

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Conclusion