Investigation of high-ozone episodes in Southern China due to distant tropical cyclones

Professor Lam, Yun Fat   (Principal Investigator (PI))

Professor Loo Becky Pui Ying   (Co-Investigator)

31

2020-01-02

2022-09-01

869000

Investigation of high-ozone episodes in Southern China due to distant tropical cyclones

distant tropical cyclones, high-ozone episodes, Southern China

Human Geography

ECF Project 36/2018

Environment and Conservation Fund

2018

Completed

Tropical cyclones (TC) related high-ozone and heat-wave episodes are increasingly becoming an environmental problem in Southern China/ Hong Kong in recent years. We hypothesize that increase in TC intensity expected in the future climate would induce stronger peripheral subsidence airflow and cause a rise in regional temperature. The escalated temperature would trigger an increase in biogenic volatile organic compounds (VOCs) and result in even higher ozone air pollution. To better understand this problem, this study will systematically study the effects of increasing TC intensity on the strength of TC subsidence and regional heat wave and ozone air quality. The study will first use observational data (both air quality and meteorology) from historical TCs to understand the relationship among the meteorological factors and ozone concentration in the presence of a distant TC. Furthermore, sensitivity simulations using WRF-CMAQ will be used to decipher how TC characteristics (position/intensity) influence local meteorology (temperature/vertical and horizontal winds/solar radiation/relative humidity, etc.) and trigger the formation of a heat wave and a high ozone condition. Success of the proposed research will provide a fundamental understanding on the formation of TC induced high-ozone heat-wave episodes so that effective mitigation may become possible.