Radar Data Characteristics of Two Severe Convective Systems Inflicting Massive Fatalities in China

The extraordinarily serious capsizing accident of the cruise ship, named Dongfangzhixing (Eastern Star), occurred at around 21:30 (Beijing Time), on June 1, 2015, in the Jianli (Hubei Province) section of the Yangtze River, causing 442 deaths. The wind damage survey over the surrounding land area of the accident showed the strongest gust wind speed greater than Beaufort 12. During 21:00-22:00, on June 1, the accident area suffered torrential rain, thunders and dense lightning flashes, and high winds. The FY-2 satellite imageries show that the area covered a quasi-circular meso-α-scale convective system with a diameter of about 250 km when the accident occurred. The Yueyang operational S-band radar reflectivity at 0.5 ° elevation shows a quasilinear convective system with a length of about 180 km sweeping the accident area. The quasilinear convective system appeared bow echoes, mesocyclones and downbursts, which caused the extraordinarily serious capsizing accident of the Dongfangzhixing cruise ship.

On June 23, 2016, a violent tornado occurred in Funing County of Jiangsu Province, inflicting 99 deaths and 846 injured. The tornado was rated EF4 based on the damage survey. FY-2 satellite imageries show that there was a quasi-circular meso-α-scale convective system with a diameter of greater than 500 km over Jiangsu, Anhui, and Shandong provinces during the period of the tornado development. Yancheng operational S-band radar observations show that the tornadic storm is a classical supercell storm with obvious overhang echoes and bounded weak echo region (BWER). The tornado occurred at hook-echo area of the supercell storm associated with the mesocyclone of base height less than 1 km above ground level, and an obvious TVS (tornadic vortex signature).