Evolution of the Total Lightning Structure of a Leading-line,Trailing-stratiform Mesoscale Convective System over Houston, Texas
Line-normal, vertical cross-sections of Houston Lightning Detection and Ranging (LDAR II) VHF radiation sources and radar reflectivity provide new insights into the three-dimensional total lightning structure and evolution of a leading-line, trailing-stratiform (LLTS) mesoscale convective system (MCS) over Houston, Texas on 31 October 2005. Similar to previous research, the overwhelming majority of VHF lightning sources occurred in the convective region with a lightning pathway extending rearward into the stratiform region, must likely associated with small, charged ice particles. Unlike previous research, the lightning pathway initially extended rearward (35 km) at a near constant height of 9 – 10 km. In less than an hour, the lightning pathway had evolved into a sloped pathway, similar to previous research, with a horizontal extent between 50 to 60 km and downward by 4 to 5 km. During the lightning pathway evolution, radar analysis showed the development of radar bright band between 3 – 4 km and an overall increase in dBZ values in the mid-levels of the stratiform region. These evolutions in the radar structure were most likely indicators of a strengthening mesoscale updraft in the stratiform region. This strengthening updraft may have lead to an increase in the growth of the small, charge carrying ice crystals giving them a greater fall speed. In addition, the mesoscale updraft may have promoted an environment conducive to in-situ charge generation in the mixed phase region just above the melting layer (radar bright band).
Brandon L Ely Richard E. Orville Lawrence D. Carey Charles L. Hodapp
Dept.of Atmospheric Sciences, Texas A&M University, College Station, Texas 77843-3150, USA
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）