Doppler radar observation and analysis of two convective gale weather events in Wuhan in May 2021

Convective gale is the most common weather phenomenon of severe storms, which causes serious disasters and is difficult to predict. Thunderstorm gales and tornado occurred successively in Wuhan on May 10 and 14, 2021. In this paper, the environmental conditions, Doppler radar echo characteristics and radar derived parameters of the two events are compared and analyzed by using conventional radiosonde and Wuhan Doppler weather radar data. The results show that: (1) Both events occur in the similar environment with high unstable energy, strong vertical wind shear and low uplift condensation height. There are convergence areas formed by multiple air streams on the ground, but the physical parameters of strong convection, energy helicity and strong weather index are significantly different between the two events. (2) The generation mechanism and radar echo characteristics of the two convective gales are different. The thunderstorm gale of "5.10" was mainly caused by the strong downdraft caused by dry and cold air in the middle layer and the phase change of precipitation particles, and by the fact that a cold thunderstorm high pressure was formed on the ground. The strong downdraft generated by the convective zone combined by multiple convective cells appears as a low-level gale core in the radial velocity field. The strong downdraft generated by the relatively isolated cell in front of the convection zone is characterized by low-level radial divergence. The "5.14" tornado is generated by supercell with hook echo, strong mesocyclone and TVS. (3) There are significant differences in the changes of vertical wind shear and SRH before the two events, indicating that the changes of ambient air flow in the two events are different. Whether such changes are applicable to the identification of the two weather conditions still needs to be studied by making statistical analysis on a large number of individual cases.