Evaluating the effect of mass continuity, smoothness, and resolution constraints on thunderstorm wind fields using Dual-Doppler 3DVAR wind retrieval

Windstorms driven by thunderstorms are among the most hazardous weather events, capable of causing significant damages. In this study, Doppler radar observations are used to analyse the internal wind structure of storm. Wind kinematic within storm systems are retrieved using three-dimensional technique based on dual-Doppler variational approach, which integrates data from C-band and X-band radar system. Sensitivity experiments were conducted by varying resolution and the weights of the cost function terms, which control the extent to which the model enforces the mass continuity equation and smoothness in the domain. The technique was applied to a thunderstorm event that occurred in the Piedmont region of Italy. The retrieved wind profiles were validated against available LiDAR observations from surface up to 2000 m in height. Results show the noticeable changes in updraft and downdraft structure depending on the cost function weights. These smoothness constraints help reduce noise and make the wind field look more realistic. The study highlights the importance of mass continuity term in producing realistic wind fields and the potential of retrieving accurate wind information from Doppler radar data. Additionally, the findings of this research contribute to a better understanding of thunderstorm dynamics and offer valuable insights for enhancing nowcasting and risk mitigation strategies for localized windstorms.