Research on Nonlinear Wind Field Retrieval Method Based on Modified VAD Analysis

The birth and development of convective storms were closely related to the three-dimensional (3D) wind field. The Doppler weather radar could use the Doppler effect to measure the radial velocity and reflect the wind field information in time. The velocity azimuth display (VAD) technology based on linear wind field assumptions and omni-directional uniform sampling was the most widely used method to retrieve three-dimensional wind fields for single Doppler radar. However, for strong convective weather systems such as typhoons and tornadoes, the spatial distribution of the internal wind field was complicated so that the assumption of linear wind field was not valid and the uniform sampling at equal azimuth intervals cannot be guaranteed due to the nonideal motion of the mobile platform, which resulted in low retrieval accuracy. This paper proposed a three-dimensional wind field inversion method based on the non-uniform sampling modified VAD technology. The nonlinear spatial distribution model of the complex wind field and the omnidirectional non-uniform sampling data model of radial Doppler velocity were established. Compared with the traditional VAD technology, the wind field retrieval results of this method can better represent the real complex wind field structure and better retrieval effects.