Research reveals greater flood risks due to slower tropical cyclone movement

A research led by the Department of Geography has revealed that the observed average moving speed (or translation speed) of tropical cyclones making landfall over the coast of China dropped by 11% between 1961 and 2017. These slow-moving tropical cyclones brought about 20% more local total rainfall on average when compared with fast-moving ones, resulting in greater flood risks in the region.

The study also found that the occurrence of tropical cyclones with lower moving speeds and higher total rainfalls became more frequent after 1990 in the Pearl River Delta.

The research team led by Dr Li Jianfeng, Assistant Professor of the Department of Geography, studied 406 tropical cyclones which made landfall and lasted for more than two days over the coast of China, and specifically the Pearl River Delta where Hong Kong is located, between 1961 and 2017. The discovery offers invaluable insights that will enable the development of better flood management and adaptation strategies in the coastal region of China which is under threat due to tropical cyclones.

The research team led by Dr Li Jianfeng revealed that the observed average moving speed of tropical cyclones making landfall over the coast of China dropped by 11% between 1961 and 2017.

(Left) Dr Li Jianfeng, Assistant Professor of the Department of Geography at HKBU; (Right) Professor David Chen Yongqin, Professor of the School of Humanities and Social Science at CUHK-Shenzhen and the Department of Geography and Resource Management at CUHK, and key member of the research team.