Analyzing the local and climatic conditions affecting the urban overheating magnitude during the Heatwaves (HWs) in a coastal city: A case study of the greater Sydney region

Hassan Saeed Khan; Mattheos Santamouris; Riccardo Paolini; Peter Caccetta; Pavlos Kassomenos

doi:10.1016/j.scitotenv.2020.142515

Analyzing the local and climatic conditions affecting the urban overheating magnitude during the Heatwaves (HWs) in a coastal city: A case study of the greater Sydney region

Sci Total Environ. 2021 Feb 10;755(Pt 1):142515. doi: 10.1016/j.scitotenv.2020.142515. Epub 2020 Sep 24.

Authors

Hassan Saeed Khan¹, Mattheos Santamouris², Riccardo Paolini², Peter Caccetta³, Pavlos Kassomenos⁴

Affiliations

¹ Faculty of Built Environment, University of New South Wales (UNSW), Sydney, NSW 2052, Australia; Data-61, The Commonwealth Scientific and Industrial Research Organization (CSIRO), Underwood Ave, Floreat, Perth, WA 6014, Australia. Electronic address: hassan.khan@unsw.edu.au.
² Faculty of Built Environment, University of New South Wales (UNSW), Sydney, NSW 2052, Australia.
³ Data-61, The Commonwealth Scientific and Industrial Research Organization (CSIRO), Underwood Ave, Floreat, Perth, WA 6014, Australia.
⁴ Department of Physics, University of Ioannina, GR-45110 Ioannina, Greece.

PMID: 33035986
DOI: 10.1016/j.scitotenv.2020.142515

Abstract

Urban overheating coincides with Heatwaves (HWs) and the thermal stress might get amplified in cities. To predict the interactions between urban overheating and HWs, the surface energy balance response to HWs is crucial. HW is a regional phenomenon and the climatic conditions may influence the local conditions to alter the energy budget contrast between a city and its adjacent peripheral areas. The interactions between the urban overheating and HWs are explored in a coastal city (Sydney Australia), also in the proximity of dry landmass, while considering the site characteristics, distance from the coast, and the population density. A positive response between urban overheating and HWs is reported. Advective heat flux in the form of a dualistic circulation system is found responsible for exacerbating the urban overheating magnitude (ΔT) during the HWs and altering the available energy balance. Land-coastal distance is also found as an important contributor in magnifying the urban-suburban temperature contrast. Considering the future urbanization in western Sydney, surfaces capable of retaining higher moisture content are prescribed to reduce the occurrence of extreme HW events. Activation of the ventilation corridor for the coastal wind penetration in western Sydney is another recommendation of this study.

Keywords: Climatic conditions; Energy balance; Heatwaves; Land-coast distance; Site characteristics; Urban overheating.