闪电CPT事件的宽带综合观测及其物理过程研究

项目名称： 闪电CPT事件的宽带综合观测及其物理过程研究

项目编号： No.41205002

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 大气科学学科

项目作者： 张阳

作者单位： 中国气象科学研究院

项目金额： 26万元

中文摘要： CPT（Chaotic pulse trains）是闪电过程中的一种重要放电事件，以不规则脉冲簇为典型特征，作为继后回击前先导阶段的多发事件，不仅伴随着低频脉冲电场变化，而且具有较强的高频辐射。目前，有关CPT事件的观测资料较少，其发生规律、发展特征及物理机制仍不明确。本项目拟针对CPT事件开展宽带多参量同步综合观测，获取该事件的宽带辐射场、电场变化、光辐射等观测资料，分析该事件的脉冲特征参数和所伴随闪电过程的特点，明确其时频域特征和发生规律；并利用双站宽带干涉仪对CPT事件开展同步观测，获取该事件产生的VHF辐射源三维定位资料，分析研究该事件的VHF辐射源时空位置及通道发展特征，对比研究该事件与K过程、预击穿过程的异同以及与企图先导、直窜先导等其它闪电放电子过程的关系，探讨CPT事件的发生物理过程。该研究将深化对CPT事件放电特征及物理过程的认识，促进对引发继后回击的放电过程的理解。

中文关键词： 闪电；不规则脉冲簇；不规则先导；综合观测；物理过程

英文摘要： As an important discharge event generated by lightning discharge, CPT (chaotic pulse trains) with typical characteristics of irregular pulse, pulsed electric field change in low frequency and strong HF radiation, can be often found during the leader before subsequent return stroke. Up to now, it is not enough to understand the occurrence regularity, propagation characteristic and physical mechanism due to the lack of special observation. In the study, the data about broadband radiation field, electric field change and optical radiation are acquired by the broadband comprehensive observation with synchronous multi-parameter. Based on the analysis of the parameters of pulse trains and the properties of corresponding lightning event, the characteristics in time-frequency domain and occurrence regularity of CPT event are investigated. At the same time, the location data of VHF radiation source generated by CPT event are recorded by dual-station broadband interferometer, and the characteristics of spatio-temporal location of radiation source and channel propagation are analyzed. Also, the differences and similarities between CPT event, K process and preliminary breakdown process are compared, and the correlation between CPT event and other sub-processes of lightning discharge, including dart leader and attempted lead

英文关键词： lightning；chaotic pulse trains；chaotic leader；comprehensive observation；physical process