Maximum wind radius approximation for parametric typhoon model combining operational forecast model and its application to storm surge and wave predictions

Abstract

Parametric typhoon models reproduce realistic atmospheric pressure and wind fields during a typhoon. They require much less computation than planetary boundary layer models, allowing rapid coastal hazard estimations such as storm surges and waves. In these models, the maximum wind radius (Rmax) is a crucial parameter determining a wind field with the typhoon’s track and central pressure. This study proposes a new approach to Rmax estimation to generate accurate wind and pressure fields using numerical model data. We use the parametric typhoon model based on the basic vortex model. The track and central pressure of typhoons are obtained from the best track archives of the Joint Typhoon Warning Center (JTWC). Rmax was estimated hourly using circle fitting methods from the National Centers for Environmental Prediction (NCEP) Global Forecast System (GFS) data. We tested this approach on five typhoons that passed near the Korean peninsula from 2016 to 2020. We evaluated the timeseries of Rmax with the JTWC archives. In addition, the prediction accuracy of storm surge and wave was compared using the reproduced wind field with Korea Operational Oceanographic System (KOOS). We also performed sensitivity tests for Rmax. This approach was tested on Typhoon Hinnamnor in 2022 with typhoon information from the Korea Meteorological Administration (KMA).