Work

Satellite‐Derived Upper‐Level Vorticity as an Indicator of Short‐Term Typhoon Intensity Evolution

Year: 2026

Type: article

Abstract: Accurate short‐term tropical cyclone (TC) intensity forecasting remains challenging because rapidly evolving inner‐core structures are difficult to observe at sufficiently high temporal resolution. Here, we derive an area‐mean upper‐level vorticity indicator (VORm) from minute‐scale atmospheric motion vectors retrieved from the Fengyun‐4B Geostationary High‐speed Imager (FY‐4B/GHI) using the Single‐Plane Assumption–Fast Approximate Barnes Interpolation framework. Analysis of western North Pacific TCs shows that VORm closely follows the broad evolution of storm intensity while retaining substantial high‐frequency structural variability. VORm exhibits a strong contemporaneous association with TC intensity and retains information related to subsequent 6‐hr intensity change after accounting for the current intensity and preceding intensity tendency, indicating potential value for short‐term intensity prediction. Forecast experiments further demonstrate this predictive potential. In the linear framework, incorporating VORm reduced the pooled 6‐hr RMSE from 6.27 to 5.97 kt, indicating additional predictive information beyond conventional intensity and environmental predictors. In the nonlinear XGBoost framework, VORm further reduced the RMSE from 6.26 to 6.18 kt even when the preceding 6‐hr intensity tendency was explicitly included, indicating that VORm still provides additional predictive information beyond recent intensity evolution. Because FY‐4B/GHI winds and the derived vorticity can be obtained with very low latency, this approach offers a practical pathway for rapidly incorporating high‐frequency inner‐core structural information into short‐range TC intensity forecasting.

Source: AGU Advances

DOI: 10.1029/2026av002688