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Lecture 1: Sky River, Concept, Theory, and Experiment |
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Time |
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10:40 – 11:00 am |
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Speaker |
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Prof Guangqian Wang, Tsinghua University |
Abstract
A brief introduction to the speaker's and his collaborators' recent study of Sky River is given in this talk, and the implications for future research are also discussed. Based on meteorological data and reanalyzed data, they found that there exist highly structured water vapor conveyance systems in the troposphere of the atmosphere. The water vapor conveyance systems have higher vertically integrated flux than their immediate environments, consisting the dominant channels from local scale to global scale for atmospheric water vapor transfer. The water vapor transfer systems in the troposphere share the similarity of having high water (vapor) conveyance with land surface rivers and thus can be referred to as "River in the Sky", or simply "Sky River". Sky River is different from “atmospheric river” essentially in that it is a global system, where water vapor are concentrated and conveyed by atmospheric circulations, rather than the transient and local high flux belts found in previous studies. Studies on the Sky Rivers will help us have a new vision about global atmospheric water vapor transfer and a better understanding of global water cycle.
About the speaker
Prof Guangqian Wang received his PhD from Tsinghua University in 1989. He furthered his career in Tsinghua University in 1992 as an Associate Professor and is currently a Professor of Hydraulic Engineering.
Prof Wang's research focuses on hydraulics and river dynamics, soil erosion and sediment transport in river basins, and hydro-informatics. Prof Wang was elected a member of Chinese Academy of Sciences and serves as a member of the Editorial Board of Journal of Hydro-environment Research.
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Lecture 2: Effect of Climate Change on Urban Areas |
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Time |
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11:00 – 11:20 am |
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Speaker |
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Prof Harindra Joe Fernando, University of Notre Dame |
Abstract
The confluence of urbanization and climate change may have adverse effects on the quality of urban life as well as the sustainability of cities, where environmental and anthropogenic factors appear to exacerbate climate change impacts on urban areas. Such impacts become more pronounced in coastal cities as the nearby waterbodies are significantly affected by climate variability, thus modifying sea/land breeze, local hydrology and snowfall. A downscaling study from climate (~ 100 km) to pedestrian (~ 2m) scales was conducted to assess the climate change impacts on Chicago metropolitan area that abuts a large great lake, with a focus on the Urban Heat Island (UHI). A model chain was used, that included one way nesting from global climate (Community Atmosphere Model, CAM), to regional climate (Weather Research and Forecasting model, WRF, and its urban version), to microscale (ENVI-met) models. The performance of the nested mesoscale and microscale models were evaluated against the present-day observations, with mesoscale observations obtained from publicly available data sites and microscale measurements from a dedicated field study conducted in downtown Chicago. A simple building-energy model is developed and used in conjunction with the microscale model output to calculate future energy demands of individual buildings. A substantial increase of energy consumption was noted for future (till the year 2080) climate. Potential UHI mitigating strategies, such as modifying rooftops (green and cool roofs) were investigated. Results show that the efficacy of green and cool roofs is dependent on the fraction of roof modification, degree of urbanization as well as background meteorology and turbulence. The lowered wind speeds and vertical mixing near the rooftops during daytime cooling at roofs may lead to stagnation of the air close to the surface, causing potential air quality deterioration. The selection of cool and green roofs for UHI mitigation therefore should be done with circumspection, considering the competing attributes of their influences.
About the speaker
Prof Harindra Joseph Fernando received his PhD in Geophysical Fluid Dynamics from the Johns Hopkins University in 1983 and furthered his post-doctoral research in environmental engineering sciences at the California Institute of Technology. He moved to Arizona State University (ASU) in 1984 as an Assistant Professor and was appointed the founding Director of the Center for Environmental Fluid Dynamics in 1994. In 2010, he joined the University of Notre Dame and is currently the Wayne and Diana Murdy Endowed Professor of Engineering and Geosciences.
Prof Fernando received numerous awards including the Lifetime Achievement Award from the Sri Lanka Foundation (2007), the Rieger Foundation Distinguished Scholar Award in Environmental Sciences (2001) and ASU Alumni Distinguished Research Award (1997). He was also elected a Fellow of the American Society of Mechanical Engineers, a Fellow of the American Physical Society, a Fellow of the American Meteorological Society and a Fellow of the American Association for Advancement in Science.
About the Symposium
For more information, please refer to the symposium website at http://hydrosym2017.ust.hk/.
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