Analysis on a supercell storm with giant hails in Tengzhou based on dual-polarization radar observations

WU Juxiu; LIU Bin; PAN Jiawen; SUN Weijia

doi:10.19513/j.cnki.hyqxxb.20240517001

Abstract：In order to reveal the environmental and radar parameter characteristics of supercell storm with hails of 7 cm or above,the environmental physical parameters,storm parameter evolution and polarization parameters of the supercell storm with giant hails in Tengzhou are analyzed using the S-band dual-polarization radar data in Jining,combined with sounding and ground observations.The results are outlined below.(1)The severe hailstorm in Tengzhou occurs under environmental conditions of strong convective available potential energy and moderate vertical wind shear in the deep layer,with relatively large temperature difference(Δt)between 850 hPa and 500 hPa,drier middle and upper troposphere,warmer and wetter lower troposphere.(2)The supercell storm in Tengzhou producing hails of 7 cm or above has a lower average maximum reflectivity(64.82 dBZ)due to the low concentration of larger hails,but higher C-VIL(average of 82 kg·m-2),depth of ZDR column(average of 2 km)and maximum rotational velocity of mesocyclone(average of 25.2 m·s-1),which means that there are strong updrafts supporting larger hails.(3)The top height of the ZDR column continues to increase and the C-VIL remains above 80 kg·m-2,which has indicative significance for the occurrence and early warning of severe hails.The continuous increase of the top height of the ZDR column indicates the intensification of the updrafts within the storm,and the storm would further develop.The C-VIL remains at high values,showing that the storm has abundant hail particles and the probability of giant hails is higher.(4)During the vigorous development stage of the storm,the strong echo(exceeding 60 dBZ)depth is close to 8 km and the top reaches about 10 km,indicating that large hails have been generated in the upper layer,and at the same time,hails fall to the lower layer,which reveals the mechanism of sustained development of hail clouds and continuous hails on the ground.