A Case Study of Cloud-to-ground Lightning Activities in Hailstorms Under Cold Eddy Synoptic Situation
The temporal and spatial distribution of CG lightning is investigated for the 3 hailstorms caused by a same northeast cold eddy situation on 1 June 2002, by using the data from SLDN, Doppler radar and satellite. The results show that different thunderstorms present different lightning features even if under the same synoptic situation. The percentage of positive CG lightning is very high during the period of hail falling. CG flashes mainly occurred in the region with a cloud top brightness temperature lower than –50 . Negative CG ℃ flashes usually clustered in the lower temperature region and tended to occur in the region with maximum temperature gradient, while the positive ones usually spread discretely. Negative CG flashes usually occurred in intense echo regions with reflectivity greater than 50dBz, while the positive CG flashes often occur in weak and stable echo regions(10 ～30dBz) or cloud anvils, although they can be observed in strong convective regions sometimes. Almost all hail falling took place in the stage with active positive flashes, and the peak positive flash rate is a little prior to the hail events. The thunderstorm could lead to disastrous weather when positive CG lightning activities occurs in cluster. Combined with the total lightning (intracloud and CG) data obtained by LIS on TRMM, the phenomenon of high ratio of intracloud flash to CG flash in severe hailstorm has been discussed. The competition of same charge resources between different lightning types can also be helpful to explaining the cause of low CG lightning activities in severe storms.
Guili Feng Tie Yuan Yunjun Zhou
Lightning Protection Center of Shandong Province , Jinan 250031 China;Cold and Arid Regions Environm Cold and Arid Regions Environmental and Engineering Research Institute , Chinese Academy of Sciences Cold and Arid Regions Environmental and Engineering Research Institute ,Chinese Academy of Sciences,
国际会议
第13届国际大气电学会议(The 13th International Conference on Atmospheric Electricity)
北京
英文
2007-08-13（万方平台首次上网日期，不代表论文的发表时间）