Characteristics of hail cloud in southwestern China based on X-band phased array radars

In order to study characteristics of hail cloud in southwestern China, the national hail observation experiment is jointly organized by the Weather Modification Center of the China Meteorological Administration and the Guizhou Meteorological Bureau from July to September in 2021-2023. The experiment region is located in Weining county, Bijie City, Guizhou province, which is belong to Wumeng mountains of Yunnan-Guizhou Plateau in southwestern China and with frequent hailstorms in summer, causing considerable damage to crops such as flue-cured tobacco. Three X-band dual polarization phased array radars with time resolution of 1 minute, distributed as all with no more than 20 km distances, are used to obtain rapid evolution and structure characteristics of hail clouds. Some preliminary results on hail cloud characteristics have been achieved as follows. (1) According to statistics of more than 80 hail clouds by phased array radars and manual observation of ground hail, it can be found that The hail cloud characteristics include that the initial birth time of Weining hail cloud is at most 16-17 Being Standard Time, the time from birth to hail fall down is 10-20 min, the life history is 20-90 min, the hail duration is more than 2-5 min, the hail particle size range is mainly 5-10 mm, and the hail density is mostly 10-50 /m2. (2) The hail cloud in Weining county has the characteristics of pulse storm. The hail cloud is initially triggered and developed rapidly by echo from the middle layer, and convection trigger height is more concentrated at 4-6 km above sea level, which can be used as an operational indicator of hail suppression. The convection initiation height of hail cloud is related with convective available potential energy (CAPE) and relative humidity (RH), which higher CAPE and lower RH can lead to higher convection initiation height.