Numerical study of extreme waves driven by synthetic tropical cyclones in the northwest Pacific Ocean

Abstract

Extreme waves induced by extreme tropical cyclones (TCs) with a very strong intensity threaten marine production and transportation. In this paper, six tropical cyclones with a typical track and extremely strong intensity were synthesized to study the extreme waves. The data on TC tracks were extracted from the China Meteorological Administration. The historic TCs from 1949 to 2018 were classified into six groups according to their tracks, and a representative track was synthesized for each group of TCs. We applied an extremely strong intensity to the tracks for studying the extreme wave field. The synthesized track of typical track cyclones (TTCs) was based on the maximum probability of the translation distance and direction of the TC center according to historical data. The central pressure (Pc) was used to represent the TC intensity and was studied at the recurrence periods of 100, 1,000, and 10,000 years. The synthetic TC with a representative track and extremely strong intensity was called a typical tropical cyclone (TTC). The extreme wave fields driven by TTCs were simulated by Simulating Waves Nearshore (SWAN). The wind field driving the waves was calculated using the Holland parametric wind model and was well-verified with observations. This paper calculated the extreme Hs and Tp values of the return periods of 100, 1,000, and 10,000 years for six types of TTCs. It was found that the extreme Hs values were very different for each TTC. The highest Hs could reach 31.3 m in the recurrence period of 10,000 years. Followed by TTC-I with 18 m, TTC-VI was the weakest with less than 10 m. The TC track position frequency and its spatial variation of extreme intensity were discussed. The synthetic tracks were representative, and the intensity could be influenced by spatial variation. In the end, four historical typhoons with great intensity, wide impact, and serious disaster-causing effects were selected to compare with TTC. This paper can provide guidance for maritime planners.