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Abstract
Among many globally recognized environmental problems such as water scarcity, air pollution, and energy security, heat stress is one of the most severe climate-driven threats to the human society. The situation is further exacerbated in urban areas by urban heat islands (UHIs). Absent measures to ameliorate them, the problems associated with heat stress are expected to intensify due to rapid urban development coupled with climate change. One significant barrier to heat mitigation through urban engineering is the lack of quantitative attribution of the various surface processes toUHI intensity. In this seminar, the intrinsic mechanism of UHI and its quantitative attribution at a large scale will be presented. Using a newly developed sub-grid modeling framework, I will demonstrate how surface aerodynamic, hydrological and anthropogenic processes contribute to UHIs. I will further discuss how these mechanistic insights could be used to assess the effectiveness of various commonly-proposed urban adaptation strategies individually and collectively. UHIs also interact with heat waves and climate change. I will also present how UHIs interact with heat waves under present-day and future warmer climates, and how global urban temperatures change with climate change.
Bio
Dr. Lei Zhao is an Assistant Professor in the Department of Civil and Environmental Engineering at the University of Illinois at Urbana-Champaign (UIUC). He received his Ph.D. in atmospheric and environmental science from School of Forestry and Environmental Studies at Yale University. Before joining at UIUC, Dr. Zhao was a postdoctoral research fellow in the Program in Science, Technology and Environmental Policy (STEP) at Princeton University. Dr. Zhao obtained his B.S. degree in Physics and Atmospheric Physics from Nanjing University in China. His research concerns the physical and engineering processes in the Atmospheric Boundary Layer where most human activities and environmental systems are concentrated, with a particular focus on built surfaces and urban environments. He combines theory, numerical modeling, remote sensing and in situobservations, and cutting-edge statistical methods to study environmental fluid mechanics and land-atmosphere interaction that relate to urban environments, microclimatology and hydrology, climate change, climate impacts and adaptation.