5:15 PM - 7:15 PM
[AOS19-P06] Projection of the worst-case impact of storm surge in Hong Kong over next 20 years
in a changing climate: An air-wave-ocean coupled study of the typhoon Mangkhut (2018)
Keywords:storm surge, tropical cyclone, climate change, coastal flooding
Hong Kong is highly vulnerable to tropical cyclone (TC)-induced coastal hazards due to its extensive shoreline and dense economic development. With global warming and rising sea levels projected to worsen throughout the 21st century, storm surges are expected to grow in severity and impact. This study employs a high-resolution (100-m) air-wave-ocean coupled model to evaluate worst-case storm surge scenarios in Hong Kong over the next 20 years.
Three experiments were conducted based on Typhoon Mangkhut (2018): (1) the FUTURE_WARMING experiment, assessing storm surges under maximum anticipated atmospheric and oceanic warming; (2) the STRAIT_TRAVELER experiment, simulating Mangkhut avoiding landfall on Luzon Island; and (3) the COMBO experiment, combining both adverse factors. Results show that under upper-bound warming and altered typhoon tracks, storm surges could exceed astronomical tides by approximately 4.0 m in Victoria Harbor, 5.2 m in Deep Bay, and 6.2 m in Tolo Harbor, with multiple flooding peaks occurring within 24 hours. An inundation model was also implemented to estimate the maximum anticipated flooding scale, defined as the coincidence of all adverse factors. Findings reveal that approximately 57.4 km^2 of Hong Kong could be inundated (water level higher than 0.5 m), including key coastal areas such as the Central Business Districts of Hong Kong Island and Kowloon. Around 1.04 million residents would experience flooding of 0.5 m or higher, with 245,000 of them exposed to water levels of 2.0 m or greater.
These findings underscore the urgent need for proactive monitoring, improved infrastructure resilience, and robust disaster response strategies to mitigate the potential social and economic impacts of future storm surges in Hong Kong.
Three experiments were conducted based on Typhoon Mangkhut (2018): (1) the FUTURE_WARMING experiment, assessing storm surges under maximum anticipated atmospheric and oceanic warming; (2) the STRAIT_TRAVELER experiment, simulating Mangkhut avoiding landfall on Luzon Island; and (3) the COMBO experiment, combining both adverse factors. Results show that under upper-bound warming and altered typhoon tracks, storm surges could exceed astronomical tides by approximately 4.0 m in Victoria Harbor, 5.2 m in Deep Bay, and 6.2 m in Tolo Harbor, with multiple flooding peaks occurring within 24 hours. An inundation model was also implemented to estimate the maximum anticipated flooding scale, defined as the coincidence of all adverse factors. Findings reveal that approximately 57.4 km^2 of Hong Kong could be inundated (water level higher than 0.5 m), including key coastal areas such as the Central Business Districts of Hong Kong Island and Kowloon. Around 1.04 million residents would experience flooding of 0.5 m or higher, with 245,000 of them exposed to water levels of 2.0 m or greater.
These findings underscore the urgent need for proactive monitoring, improved infrastructure resilience, and robust disaster response strategies to mitigate the potential social and economic impacts of future storm surges in Hong Kong.