Abstract:
Three-dimensional wind structure of supercell hailstorms is an important research topic. Based on the data of three weather radars (CINRAD/SA) deployed at Xiamen, Longyan, and Meizhou, the echo evolution, three-dimensional wind structure characteristics and distribution changes of related parameters during a hail storm occurred in the evening of April 8, 2016 in southern Fujian (Zhangzhou) are examined by means of dual-and triple-Doppler radars retrievals in the kinetic Earth coordinate. The results are as follows. (1) In the initial and developing stages of the hailstorm system, horizontal circulation showed a cyclonic convergence in lower levels and strong ascending motions appeared inside the clouds. (2) In the mature stage of the hailstorm system, the echo top was up to 16 km. Reflectivity stronger than 60 dBz developed from 5.3 km to 9 km height, with the strongest echo reaching 74.5 dBz. A 25 km long three-body scatter spike and 32.7 km long side-lobe echoes appeared at the same time. While the cyclonic circulation existed in lower levels, anti-cyclone appeared in high level. Strong updrafts with velocities larger than 20 m/s lasted for nearly 37 min between the heights of 4-8 km. The strongest updraft of 51.06 m/s occurred at 7.5 km height in the super-cell overhang. (3) Downdraft occurred during the period of hail falling. The three-dimensional flow structure of this supercell hailstorm showed that the cyclonic airflow in the front of storm ramped up to the top of storm, forming an anticyclonic circulation there, and then gradually descended, leading to the formation of downdrafts. (4) Systemic downdrafts appeared during the weakening period of the hailstorm system, and strong echo reached the ground. (5) Dual-and triple-Doppler radar could detect the meticulous structure of the supercell hailstorm. The results are helpful for better understanding the structure of hailstorms and improving the forecast ability.