Storm Surge Calculations Using Sea Level Data

Abstract

Sea level data from the National Oceanographic Research Institute were used to calculate storm surges along the Korean Peninsula. The influences of the surface elevation data (with record interval and length) and of the tide analysis method (harmonic or response method) on calculated storm surge were compared at Masan and Yeosu during Typhoons Maemi and Ewiniar. Depending on the sea level data and tidal prediction method used, calculated surge heights differed by as much as 70 (50) cm for the maximum surge of 211 (168) cm at Masan (Yeosu) during Typhoon Maemi. Maximum surge heights calculated from 1-hour data were considerably underestimated compared to calculations from 1-minute data, giving a misleading result. The sampling interval of sea level data was more important for surge calculations (especially for sharply peaked surges) than was the sea level record length. The harmonic method using 1 year of data produced the most reliable surge calculations. However, the extended response method using a 1-month record was almost as accurate as the harmonic method using the 1-year record. The extended response method might offer a good alternative for tidal prediction when a 1-year record is unavailable, as shown for Masan during Typhoon Ewiniar.