A New Unified Numerical Model for Surge in the Northwestern Pacific

Abstract

A new finite difference modeling system with fetched variable grid system has been developed in order to predict the typhoon induced surge over the Northwestern Pacific, which system has a benefit to avoid possible numerical errors which can occur by adopting nested grid system. The grid resolution ranges from 18.3km in open ocean to 100 m near the coastal areas of interest, which can resolve the complicated coastal boundaries with reasonable resolution in the Korean coasts. The total grid number is about 1,400,000 points and the model computation can be effectively carried out with efficient time interval satisfying 5-10 Courant numbers. This system has various benefits against regular finite difference grid system. The experiment for typical typhoons such as maemi in 2003 and Nari in 2007 have been carried out to show if the system works reasonably. During Maemi passage the surge peaks of eastern South Sea occured around 21:00 (Sep.12, 2003), which is well compared with observations. The computed surge shows a generally well comparison with observations.n occur by adopting nested grid system. The grid resolution ranges from 18.3km in open ocean to 100 m near the coastal areas of interest, which can resolve the complicated coastal boundaries with reasonable resolution in the Korean coasts. The total grid number is about 1,400,000 points and the model computation can be effectively carried out with efficient time interval satisfying 5-10 Courant numbers. This system has various benefits against regular finite difference grid system. The experiment for typical typhoons such as maemi in 2003 and Nari in 2007 have been carried out to show if the system works reasonably. During Maemi passage the surge peaks of eastern South Sea occured around 21:00 (Sep.12, 2003), which is well compared with observations. The computed surge shows a generally well comparison with observations.