Analysis of Hail Weather Environmental Characteristics and Radar Identification Indexes in Cangzhou
In order to improve the ability of hail forecasting,early warning and defense,the characteristics of hail climate change,synoptic formation mechanism and radar echo in Cangzhou from 2001 to 2022 were analyzed by climatological tendency rate method and synoptic statistics method,based on conventional observation and Doppler radar data from weather stations.The results showed that:In the past 22 years,the hail disasters in Cangzhou were mostly small and medium-sized hail,and the earliest occurrence date was obviously delayed,while the latest date was obviously advanced.The annual hail frequency showed a decreasing trend.Hails occurred mostly in spring and early summer,especially in June,and occurred more frequently during 12:00 to 19:00.The northwest airstream and pre-trough were the main weather patterns causing hail in Cangzhou.The environmental parameters favorable to the occurrence of hail in Cangzhou were summarized as follows:(1)T85 ≥28 ℃;(2)K/MK ≥ 27 ℃;(3)LI/SI ≤-0.8 ℃;(4)When CAPE ≥ 1000 J·kg1,0 ℃ layer was at 2.8～5.1 km height,-20 ℃ layer was at 5.2～8.0 km height,or when Wsr ≥ 12 m·s-1,0 ℃ layer was at 2.1～3.6 km height,-20 ℃ layer was at 4.7～6.5 km height,T-Td ≤ 6 ℃ at 925 hPa.In June and July,the thresholds of hail radar identification indexes MCR,MVIL and DVIL in Cangzhou were obviously higher than those in Hebei province,while ET and HMwere close to those in Hebei province,and the extension height of strong echo HMCR ≥H-20℃.
万方数据
维普
