主办单位:中国气象局沈阳大气环境研究所
国际刊号:ISSN 1673-503X
国内刊号:CN 21-1531/P

Journal of Meteorology and Environment ›› 2022, Vol. 38 ›› Issue (3): 1-10.doi: 10.3969/j.issn.1673-503X.2022.03.001

• Articles • Previous Articles     Next Articles

Observational analysis of EF4 tornadic supercell storm in Kaiyuan of Liaoning province on July 3, 2019

Shi-bo GENG1,2(),Kui-zhi CAI2,*(),Ying WANG2,Fu-ran ZHOU3,Guang-liang XIAO2,Hai-liang HUANG2,Xiao-ling CHAI4   

  1. 1. Institute of Atmosphere Environment, China Meteorological Administration, Shenyang 110166, China
    2. Liaoning Meteorological Disaster Monitoring and Early Warning Center, Shenyang 110166, China
    3. Jinzhou Meteorological Observatory, Jinzhou 121000, China
    4. Shenyang Meteorological Observatory, Shenyang 100168, China
  • Received:2021-07-06 Online:2022-06-28 Published:2022-07-23
  • Contact: Kui-zhi CAI E-mail:gengshibo2015@163.com;59595455@qq.com

Abstract:

Based on the observational data from Doppler radar, ground automatic weather station, wind profile, and ERA5 reanalysis data, the environmental conditions, Doppler radar echo characteristics, and formation mechanism of super monomer storm accompanied by EF4 strong tornado occurred in Kaiyuan of Liaoning province on July 3, 2019 were analyzed.The results indicated that this process occurs under thermal instability, warm wet in the lower layer, and cold and dry in the upper layer.The wet convection is triggered near the ground convergence line formed by the confluence flow field of the ground trunk line and develops into a supercell storm with a tornado.The tornado occurs near the hook echo in the lower layer.The Doppler radar shows the echo characteristics of the classic supercell storm.The strong wind shear in the lower layer converts the horizontal vorticity into the vertical vorticity in the convective storm.The strong upward movement makes the downstream vorticity tilt and stretch.Therefore, the mesocyclone structure appears for the first time when the Doppler radar is at an elevation of 2.4°, i.e., 17 minutes before the tornado.Then, during the movement of the storm, the downdraft behind the storm (RFD) "depresses" the vorticity in the middle and low layers, resulting in the tornado reaching the ground.Therefore, one minute after the tornado, there is also a strong mesocyclone at an elevation of 0.5° with characteristics of tornado-like vortexes (TVS).The maximum rotation speed of the mesocyclone reaches 28 m·s-1 (reaching the strong meso-cyclone standard).Therefore, this tornado conforms to the characteristics of a "top-down" type I tornado.Due to the strong evaporation and cooling of water droplets caused by the entrainment of ambient dry air, a strong cold pool with a temperature drop of 10 ℃ in one hour appears on the ground.An excessively strong cold pool may play a key role in promoting the demise of the tornado, resulting in the demise of the tornado after about 30 minutes.

Key words: Super monomer, Tornado, Supercell, Mesocyclone, Vorticity

CLC Number: