Modeling the Electric Structure of Small Thunderstorms and Their Contribution to the Global Electric Circuit
A quasi-static model of the electric environment of a typical small thunderstorm and its contribution to current flow in the global electric circuit has been developed. In situ measurements show that a typical small thunderstorm in its mature state has two regions with different vertical electric structures: one of them corresponds to the updraft region and another, more complicated, that corresponds to the non-updraft portion of the storm. Each of the regions is modeled separately as a set of the external currents in accordance with the measured electric field profile. Using these model current sources the electric field and current density in the vicinity of the storm are calculated. An influence of a screening layer of charge near the top of the thundercloud is considered. Because of this screening layer, the modeled average contribution of a typical small storm to the global electric circuit is found to be smaller as compared to the earlier models using only a dipole electrical structure. Airplane and balloon measurements of the electric field indicate that there may be a “hole in the screening layer above the updraft region. Storm models with and without such a hole are compared to determine its effect on the current driven by the storm to the ionosphere and consider the implications of these results on the overall contribution of small storms to the global circuit.
Stanislav S. Davydenko Thomas C. Marshall Maribeth Stolzenburg
Institute of Applied Physics, Russian Academy of Sciences, 46 Ulyanova str., 603950 Nizhny Novgorod, Department of Physics and Astronomy, University of Mississippi, University, Mississippi, 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）