Analysis on the influence of fine detection technology of dual polarization weather radar on recognition ability of two tornado storms in 2021

Reflectivity and Doppler velocity measurements from the new generation weather radar provide important input for the identification and early warning of severe storms and tornadoes. After the dual polarization upgrade, the radar base data resolution has an azimuthal spacing of 1.0° and range spacing of 250 m for all observations(1.0°×250 m). To test the feasibility of improving data resolution, Hangzhou and Shenzhen Zhuzilin dual polarization radars use fine detection technology, and the data resolution can be improved to 0.5°×62.5 m /125 m. Taking two tornadoes as examples, this paper analyzes the quality of radial velocity data, compares and analyzes the echo characteristics of the tornado storms, multiple radar features and TVS recognition results under the two resolutions. The results show that: (1) Some non-velocity aliasing outliers appear in the radial velocity data, especially the radial velocity collected using stagger PRT technique, which increases the possibility of identifying false TVSs. (2) Fine resolution radar echo can better describe the characteristics of tornado storm. (3) The mesocyclone centroid position obtained from the fine resolution radial velocity data is more consistent with the tornado disaster path. Radar features such as Z_max, VIL, SHI and mesocyclone rotation speed and azimuth shear of fine resolution tornado supercell are mostly greater than those of the current resolution. The recognition times of TVSs are also greater than those of the current resolution. Therefore, without considering the radial velocity data quality, compared with the current resolution detection, fine resolution detection is more conducive to the identification of tornado storms.