HR: 1340h
AN: AE23A-0839    [Abstracts]
TI: The Possible Charge Structure of Thunderstorms and Lightning Discharge Features on the Tibetan Plateau
AU: * Zhou, Y
EM: zhouyj@ns.lzb.ac.cn
AF: Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, W.260 Donggang Road, Lanzhou, 730000 China
AU: Qie, X
EM: qiex@ns.lzb.ac.cn
AF: Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, W.260 Donggang Road, Lanzhou, 730000 China
AU: Xie, Y
EM: dlxieyr@yahoo.com.cn
AF: Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, W.260 Donggang Road, Lanzhou, 730000 China
AU: Kong, X
EM: kxz_zy@hotmail.com
AF: Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, W.260 Donggang Road, Lanzhou, 730000 China
AU: Zhang, T
EM: zhangt@ns.lzb.ac.cn
AF: Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, W.260 Donggang Road, Lanzhou, 730000 China
AU: Zhang, G
EM: zhanggs@ns.lzb.ac.cn
AF: Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, W.260 Donggang Road, Lanzhou, 730000 China
AU: Zhang, Y
EM: zhangyj@ns.lzb.ac.cn
AF: Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, W.260 Donggang Road, Lanzhou, 730000 China
AB: The Tibetan Plateau exerts a profound thermal and dynamical influence on the atmospheric circulation because of its high elevation and great dimension. The Plateau is usually covered by active cumulus convection in the summer and there are many thunderstorms, hailstorms, showers and convective clouds on the central Plateau. In this paper we present an analysis of the characteristics of thunderstorms and lightning discharges on the central Tibetan Plateau by using the ground-based observation data from field mill, slow antenna, fast antenna system, high-speed digital camera and VHF radiation pulse location technique in the summer of 2003 and 2004. It has been found that the thunderstorm on the plateau is usually accompanied with hail fall and the surface electric field underneath thunderstorm usually shows the same polarity as clear sky. The characteristics of both surface electric field and lightning discharges suggest that there was a larger-than-usual positive charge region in the bottom of thundercloud, and resulted in a tripole charge structure in thunderstorm. Precipitation particles, especially solid particles, are the main contributors of the lower positive charge region. This indicates that collision between ice crystals and rimed graupel particles is the dominant mechanism for charge separation in thunderstorms. The cloud-to-ground (CG) discharge takes about 21.6% of all lightning discharges with a positive CG ratio of about 18.8%. A long-duration intracloud discharge process between the lower positive charge region and the middle negative charge region in the cloud usually occurred just before the negative CG discharge, and it seems to be a necessary condition for the negative CG. Acknowledgments. The research was supported by the National Natural Science Foundation of China (Grant No. 40135010 and 40325013 ).
DE: 3324 Lightning
DE: 3304 Atmospheric electricity
DE: 3314 Convective processes
SC: Atmospheric and Space Electricity [AE]
MN: 2004 AGU Fall Meeting