Exploring typhoon prediction and convective bursts through integration of a numerical model after vortex initialization with AI weather forecasting

Typhoon Bebinca in 2024 experienced a nearshore outbreak (a rapid intensification (RI) near the coast), making accurate forecasting of unpredictable tracks and intensities highly challenging. The AI model is superior to the numerical model for typhoon track prediction but performs worse for intensity forecasting. Vortex initialization is an effective approach to further improve numerical prediction via cycle assimilation, accounting for multiple relocating TC centers and adjusting the typhoon initial structure. In addition, by integrating numerical runs with an AI weather model through real-time dynamic weight correction of the forecast, the predictive skill is further improved. For example, it can reduce the deviation of 72-h track forecasting by 25% compared with the numerical model and decrease the intensity deviation by 2% and 56% relative to the numerical run and AI forecasts, respectively. On the basis of the best-performing forecasting, the inner-core convective burst (CB) characteristics are illuminated. The attributions of the nearshore outbreak and RI of Typhoon Bebinca are examined. From the viewpoint of bottom-up convection growth, the CB is associated with the energy supply from the high-boundary-layer CAPE, the following upward-developing secondary circulation, and accompanying latent heat release of hydrometeors. The contracted radius of maximum winds (RMW) and increased inertial stability within the inner core region effectively prevent the escape of the high-energy atmosphere and favor rapid intensification and maintenance of the offshore burst of a typhoon. The intensifying secondary circulation further promotes the primary circulation of the TC and RI processes through the gradient wind balance. 2024年强台风贝碧嘉近岸爆发快速增强, 预报极具挑战.将数值预报和AI模型相结合, 并融入涡旋初始化循环同化预报技术,以及动态权重释用预报技术等, 可在不同程度上提升台风路径和强度预报.比如, 72h路径预报偏差较数值模式降低25%, 强度偏差较AI预报降低56%.基于预报分析, 发现台风近岸爆发快速增强, 与内核对流爆发,次级环流增强促进主环流发展, 边界层高CAPE,深对流潜热加热持续供能, 内核惯性稳定度增加防止高能大气外逸等有关.