Coastal flooding by tropical cyclones and atmospheric rivers

Abstract

Southeast China is the most developed region in China. Climate change and rapid urbanization make this region particularly vulnerable to flooding. Due to the weaknesses of real-time flood forecasting, it is significant to do upstream forecast and have more time for flood control. Atmospheric rivers (ARs) and tropical cyclones (TCs) are both complex systems that are triggering flood events. This thesis is to explore the relationship between ARs and TCs and find their combined impact on coastal flooding. From the statistical analysis, we can find that the concurrence between ARs and TCs is not an uncommon event. There are about 76% of TC events are related to AR for individual TC events and more than 50% of TC events are related to AR during its landfall period. We selected three typical cases from the perspective of temporal and spatial association to analyze and explore the interaction between TCs and ARs and their inland impact in detail. We can conclude that both TCs and ARs can cause flood hazards in the coastal region by producing extreme wind and heavy rainfall. The difference between them is that the inland impact of TCs is induced simultaneously, however, the inland impact caused by ARs is more unpredictable and changeable. The TCs and ARs kept their mechanism and have an impact on each other at the same time. For example, the tracks of ARs and TCs are both influenced by mid-troposphere steering flow and some interaction can happen, the inland AR can be induced by TCs. The environmental conditions which are favorable for TCs and ARs are not similar, but summer is a peak season for TCs and ARs genesis and make it possible that the concurrence of ARs and TCs over China land during summer is a high-frequency event.

Date of Award	2021
Original language	English
Awarding Institution	The Hong Kong University of Science and Technology
Supervisor	Mengqian LU (Supervisor)