The mechanism of after-runner storm surge along the north coast of Vietnam

Abstract

In this study, the mechanism of abnormal surge along the North coast of Vietnam after the Typhoon Kalmaegy (September/2014) landfalled at Quang Ninh province was analyzed based on the observation data and the results of a coupled model of surge, wave and tide (called SuWAT), by using asymmetric and symmetric wind and pressure fields. For the asymmetric wind and pressure field, the Weather Research and Forecasting (WRF) model is used, while for the symmetric wind and pressure field, a parametric wind and pressure model is used. In the case using wind and pressurefields from the WRF model, the case not consider the effect of tail wind field after the typhoon landfalled is also conducted in order to assess the role of the wind field before and after the typhoon landfall on the surge. The results show that the case use wind and pressure field from the WRF model showed better agreement with observations data. It is due to the WRF model was well simulated the wind and pressure field before and after the typhoon landfall. The strong tail wind is mainly cause the high of surge in the area. This research results will be useful in warning and forecasting storm surges in the area.