Understanding the relationship between urban blue infrastructure and land surface temperature

Caiyan Wu; Junxiang Li; Chunfang Wang; Conghe Song; Yu Chen; Maroš Finka; Daniele La Rosa

doi:10.1016/j.scitotenv.2019.133742

Understanding the relationship between urban blue infrastructure and land surface temperature

Sci Total Environ. 2019 Dec 1:694:133742. doi: 10.1016/j.scitotenv.2019.133742. Epub 2019 Aug 2.

Authors

Caiyan Wu¹, Junxiang Li², Chunfang Wang³, Conghe Song⁴, Yu Chen¹, Maroš Finka⁵, Daniele La Rosa⁶

Affiliations

¹ School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, PR China.
² School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, PR China; Shanghai Key Laboratory of Urbanization Ecological Processes and Eco-restoration, East China Normal University, Shanghai 200241, PR China; Institute of Eco-Chongming, 3663 North Zhongshan Road, Shanghai 200062, PR China. Electronic address: jxli@des.ecnu.edu.cn.
³ Shanghai Municipal Center for Disease Control & Prevention, Shanghai 200336, PR China. Electronic address: wangchunfang@scdc.sh.cn.
⁴ School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, PR China; Shanghai Key Laboratory of Urbanization Ecological Processes and Eco-restoration, East China Normal University, Shanghai 200241, PR China; Department of Geography, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
⁵ School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, PR China; SPECTRA Centre of Excellence EU at Slovak University of Technology in Bratislava (STU), 81243 Bratislava, Vazovova 5, Slovak Republic.
⁶ Dipartimento Ingegneria Civile e Architettura, Università di Catania, Viale A. Doria 6, 95126 Catania, Italy.

PMID: 31756833
DOI: 10.1016/j.scitotenv.2019.133742

Abstract

Urban heat island (UHI) effect has serious negative impacts on urban ecosystems and human well-being. Mitigation of UHI using nature-based solutions is highly desirable. It was well known that urban green infrastructure (UGI), i.e., urban vegetation, can effectively mitigate UHI effect. However, the potential of urban blue infrastructure (UBI), i.e., urban surface water, on UHI mitigation is not well understood, although its potential to lower UHI effect via evaporation is similar to the biophysical mechanism of evapotranspiration through vegetation. In this paper, we study the relationship between UBI and land surface temperature (LST) in Wuhan city in central China, using a normalized difference water index (NDWI), maximum local cool island intensity and the maximum cooling distance as indicators for the cooling effects of UBI, respectively. We found a significant negative linear relationship between mean LST and NDWI after NDWI passes a critical threshold value. NDWI is an effective biophysical parameter to delineate the spatial distribution of UBI. The cooling effects of UBI are influenced both by its size and shape. Water surface temperature decreased logarithmically with increasing UBI size, critical threshold values of UBI size corresponding to maximum cooling efficiency do exists. Maximum cooling distance and maximum local cool island intensity are also affected by the shape and size of UBI, and exhibit seasonal and spatial variations. These results provide insights for urban landscape planning regarding how to use UBI as a nature-based solution to improve urban thermal environment.

Keywords: Cooling effect; Land surface temperature; Normalized difference water index; Urban blue infrastructure; Urban heat island.