International research on maritime continent giant thunderstorms in intertropical convergence zone(ITCZ) and their contribution to the global electric circuit

热带辐合带（ITCZ）海洋大陆巨型雷暴的国际研究及其对全球电路的贡献

基本信息

批准号：
14254001
负责人：
KAWASAKI Zen-ichiro
金额：
$ 25.04万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2004
项目状态：
已结题

项目摘要

This report is devoted to realize an operational VHF broadband digital interferometer(DITF) for thunderstorm observations. The VHF broadband DITF is a system to locate the source of a wideband impulsive EM wave caused by lightning progression in VHF band. The source locations of the VHF impulses provide not only the image of lighting progression channel but also the charge distribution inside thunderclouds.A new type of lightning location and monitoring system has been developed based on a technique of VHF broadband digital interferometry. The remarkable feature of the VHF broadband DITF is its ultra-wide bandwidth and implicit redundancy for estimating the location of a VHF impulse source. The schematic of broadband digital interferometery is calculating phase difference between EM signals captured by two properly separating antennas, and this procedure is applied to each Fourier component of broadband EM pulses. Since it is well known that one lightning flash emits a few thousands of … More VHF impulses mainly from the tip of breakdown, the location for their sources are equivalent to imaging the lightning channel development. As a first step of the developing, we install an experimental system and conduct field campaigns for lightning observations.The accuracy or error estimation of the VHF broadband DITF is discussed to validate the performance. A computational approach is carried out calculating the EM fields and the effectiveness of the proposed technique is demonstrated numerically. The obtained by the experimental DITF are compared with observations by video camera, classical narrowband interferometer, weather radar, and so forth. The error evaluations in terms of dispersions, Fourier components, and interactions are also discussed.The use of the VHF broadband DITF to study charge distribution inside thunderclouds is proposed. Case studies focused to positive CG flashes during winter thunderstorm season, the altitude and the quantity of positive charges inside thundercloud, J- or K- processes, and the leader progressions especially its initiation of negative CG flashes are implemented. Real-time monitoring of thunderstorm is also attempted. The advanced system is developed on the recent progress of electronics to obtain highly performance. A VHF broadband DITF on board a satellite is being planed as well.Then the published papers about the results of this research are listed. Less

该报告致力于实现用于雷暴观测的操作VHF宽带数字干涉仪（DITF）。 VHF宽带DITF是一个定位由VHF频带中的闪电进展引起的宽带冲动EM波的来源的系统。 VHF冲动的源位置不仅提供了照明进程通道的图像，还提供了ThunderCloud内部的电荷分布。一种新型的闪电位置和监视系统是根据VHF宽带数字干扰技术开发的。 VHF宽带DITF的显着特征是其超宽带宽和隐式冗余，用于估计VHF脉冲源的位置。宽带数字干涉的示意图是计算两个正确分离天线捕获的EM信号之间的相位差，并且将此过程应用于宽带EM脉冲的每个傅立叶分量。由于众所周知，一个闪电闪光灯散发出数千个…更多的VHF冲动主要是从崩溃的尖端发出的，因此其来源的位置等同于对闪电通道的开发进行成像。作为开发的第一步，我们安装了一个实验系统，并进行了闪电观察的现场活动。讨论了VHF宽带DITF的准确性或误差估计以验证性能。进行了计算方法来计算EM场，并在数值上证明了所提出技术的有效性。通过摄像机，经典的窄带干扰，天气雷达等进行了比较，通过实验ditf获得的结果进行了比较。还提出了VHF宽带DITF研究ThunderClouds内部的电荷分布的使用。案例研究集中在冬季雷暴季节的正面CG上，雷霆，J-或K过程中的高度和正电荷的数量以及领导者的进度，尤其是其负面CG闪光的计划。还尝试了对雷暴的实时监测。先进的系统是根据电子产品最新进度获得高度性能的。卫星上的VHF宽带DITF也是行星。然后列出了有关这项研究结果的发表论文。较少的