An analytical model for boundary layer wind velocity profiles of landfalling typhoons based on field measurements

Low-level jets (LLJs) below 100 m height are frequently observed in typhoon boundary layer wind through field measurements. However, their occurrence patterns and characteristics remain inadequately quantified. Existing empirical wind profile models (e.g. power-law model, log-law model, Vickery model) often fail to capture the full vertical structure of typhoon winds, particularly in the near-surface layer where deviations are significant due to the influence of low-level jets. This study presents a comprehensive analysis of boundary layer wind profiles based on field measurements from multiple landfalling typhoons across various surface exposure categories, typhoon structural partitions and wind speed ranges. Statistical analyses indicate that LLJs are more prevalent under high wind speeds within the back eyewall region. In response, an analytical wind profile model is proposed that accounts for the LLJ phenomenon and the reverse “C”-shaped vertical profile typical of typhoon wind fields. Empirical formulations for model parameters were developed as a function of the 10m reference height wind speed(U₁₀), calibrated through nonlinear regression. The proposed model demonstrates improved accuracy in replicating measured typhoon wind profiles compared to conventional models. Validation with representative typhoon events confirms the model's applicability and robustness for engineering wind load assessments in typhoon-prone regions.