A Comparative Study of Typhoon Hato (2017) and Typhoon Mangkhut (2018)-Their Impacts on Coastal Inundation in Macau

Typhoons Hato (2017) and Typhoon Mangkhut (2018) struck the Pearl River Delta, China, in two consecutive years, causing intense flooding and severe damage along the coast, especially in Macau. These two typhoons are extreme events because of their record-breaking storm tides, and they are typical typhoons in terms of their track forward directions, which affect the coast of Guangdong Province, China. This paper analyzes and compares the physical processes of these two major typhoons. We first report the results of our posttyphoon surveys in Macau and the constructed inundation maps for both typhoon events. The inundation maps in conjunction with measured wind, atmospheric pressure, and wave data are used to validate a package of numerical models that simulate fully coupled tide-surge-wave fields during a typhoon. We quantify storm surges and wave heights in the Pearl River Delta. The surge around Macau was mainly affected by wind, while atmosphere pressure and ocean waves played a secondary role. In additional to inundation depth, we also investigate inundation durations and flow velocities. Typhoon Mangkhut made its landfall at much lower tidal level than that of Typhoon Hato. However, Typhoon Mangkhut generated much larger storm surge with larger affected areas and significantly longer inundation durations. We attribute the causes mainly to Typhoon Mangkhut's storm size, which was almost three times larger than that of Typhoon Hato.