ANALYSIS OF A STRONG CLASSIC SUPERCELL STORM WITH DOPPLER WEATHER RADAR DATA
Zheng Yuanyuan Yu Xiaoding(Anhui Weather Forecast Office, Hefei 230061) (CMA Training Center, Beijing 100081)Fang Chong Bao Wenzhong Xie Yifeng Zhou Kuen Lu Dachun1 Liu Yong(Anhui Weather Forecast Office, Hefei 230061)
In the paper, a detailed analysis is made, by using the Hefei Doppler Weather Radar data on a strong classic supercell storm which occurred on 27 May 2002 in the north of Anhui province. This supercell storm originated from a multicell storm which first appeared at 13:20 on 27 May 2002 between the Haozhou and Woyang county in the northwest of Anhui. The storm moved in southeast east direction during the following several hours. Around 16:00, the storm evolved into the supercell storm, and remained as a supercell for the following 1 hour. After 17:00, it lost its supercell identity and evolved into a squall line. The squall line moved into north Jiangsu province around 21:00. At 16:55, the supercell storm attained its maximum strength, located near Bengbu city. The detailed structure of the supercell at this moment is analyzed in the paper. On the low elevation reflectivity maps, a typical hook echo appeared at the right rear flank of the storm and the maximum reflectivity was over 70 dBz. Violent gust wind and severe hail was observed in Bengbu city. There were two outflow associated with the supercell, lying to the southwest and southeast of the storm, respectively. The shape of the front flank of the supercell was an inverted "V", which was also a typical feature of supercell storm. Along the low level inflow and cross the maximum reflectivity core, a vertical cross section of the reflectivity was made, which displayed a large BWER (vault), extensive and strong echo overhang and the echo wall to the left of the BWER. The maximum reflectivity was within a narrow vertical zone along the echo wall, with the value over 70 dBz. The corresponding low to middle elevations radial velocity maps showed a strong mesocyclone, with rotation velocity over 22 m/s. At the top of the supercell storm, strong divergence was existing , with the difference between the positive and negative velocity attaining 63 m/s. Hence, this storm possessed almost all typical features of supercell hailstorms. Although only 11 mm diameter hail was observed at the weather station in Bengbu city, the real maximum size of hail must be much larger than 11 mm. Another point needs to not is that although strong mesocyclone appears, no tornado was observed. Further study is needed to distinguish between non tornado supercell and tornado supercell, especially when a strong mesocyclone is present. The features of supercell such as hook echo, BWER, mesocyclone and storm top divergence lasted one hour. Meanwhile, mean wind of the storm bearing layer was northwest west wind, and the supercell moved to 30°right to the mean wind, so it was a right moving supercell storm.
【Fund】： 中国气象局课题“安徽省准河流域梅雨期 (雨季 )中尺度系统发生、发展及预报方法研究”;; 安徽省气象局课题“省短时灾害性天气预警系统”;; 教育部优秀年轻教师研究基金
【CateGory Index】： P412.25
【CateGory Index】： P412.25