PhD Oral Exam - Jiwei Zou, Building Engineering

When studying for a doctoral degree (PhD), candidates submit a thesis that provides a critical review of the current state of knowledge of the thesis subject as well as the student’s own contributions to the subject. The distinguishing criterion of doctoral graduate research is a significant and original contribution to knowledge.

Once accepted, the candidate presents the thesis orally. This oral exam is open to the public.

Abstract

Climate change has led to prolonged, more frequent, intense, and severe extreme weather events, such as summertime heatwaves, creating many challenges on the economy and society and human health and energy resources. For example, the 2010 and 2018 heatwave in Quebec, Canada, resulted in about 280 and 93 heat-related deaths, and there were around 500 fatalities due to overheated indoor environments in 2021 around entire Canada. Therefore, it is imperative to evaluate historical urban overheating conditions as well as predict the future scenarios. Considering a large temporal scale when assessing future climates (up to hundred years) and a large spatial scale when assessing the microclimate of an entire urban area, this thesis developed a representative method which could serve for both large temporal and spatial scale to select typical and extreme scenarios for overheating assessment.

Firstly, future indoor and outdoor overheating conditions are evaluated in Canadian cities by assessing the effectiveness of a reference year selection method. Onsite long-term climate data sourced from the Coordinated Regional Climate Downscaling Experiment (CORDEX) is bias-corrected and analyzed to evaluate overheating conditions in Montreal, Toronto, and Vancouver under various future climate scenarios. Secondly, the typical and extreme days are selected from reference year as the input of CityFFD-CityBEM co-simulation for assessing climate change impacts on urban overheating in downtown Montreal. The analysis points out a shift from mild thermal stress to extreme heat stress under future climate conditions, highlighting the critical need for interventions in urban design and infrastructure to maintain outdoor comfort. Last but not least, this thesis expands the scope by developing a spatial and temporal representative method combined with Weather Research and Forecasting (WRF) and CityFFD simulations to evaluate overheating across Montreal. The results emphasize the importance of selecting representative locations for simulations to accurately capture the varying microclimate conditions across the city. Findings suggest significant increases in urban heat, necessitating targeted mitigation strategies.

The contributions of this thesis are significant in advancing the understanding of urban overheating dynamics and mitigation strategies. It provides municipalities and urban planners with validated tools and methods to forecast and counteract the adverse effects of urban overheating. This research underscores the critical role of detailed, localized climate simulations in urban planning and highlights innovative strategies to enhance urban resilience against climate change-induced overheating.