A beta-advection typhoon track model and its application for typhoon hazard assessment

Abstract

Typhoon track model plays an important role in typhoon wind hazard estimation. In this article, a beta-advection model is developed to simulate the typhoon track over the western North Pacific (WNP). The typhoon motion is driven by two effects, the steering flow and beta drift. The steering flow is modeled as the linear combination of the 850 ​hPa height large scale flow and 250 ​hPa height large scale flow. The spatially varying weights are estimated from the 20th Century Reanalysis dataset for each 5 ​° ​× ​5 ​° square in WNP. The large scale flows at both heights are simulated as multivariate random process based on the fact that the energy spectrum of the geostrophic turbulence follows a “-3” power law. As another driving force of typhoon motion, the beta drift is calculated by solving the non-divergent barotropical vorticity equation. The adequacy of the present model is validated by the comparison between the typhoon translation velocity inferred from the best-track dataset and that simulated by the model. Finally, integrated with an intensity model, the beta-advection model is used to analyze the statistics of typhoon key parameters and typhoon wind hazard along the southeast coast of mainland China.