Lightning Observation in Inland Plateau Area of China

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A few data on natural and artificially triggered lightning have been obtained during a comprehensive field experiment carried out in the summer of 1997, in inland plateau area of China. Following are some of the preliminary results of data analysis.For natural discharges, analyzes on the data of both discharge sources by wide-band interferometer and electric field change by capacitive antennas indicate that a intra-cloud discharge usually begins with a negative leader initiating from the lower negative charge center and then propagating towards the upper part of the cloud. The comparison of discharge noise sources with radar echoes also show that the noise sources mainly concentrated within a up and a low two layrs in the cloud.For artificially triggering lightning, we have succeeded firstly on altitude triggered positive discharge lightning with a bi-directional leader process in inland plateau area of China. According to the simultaneous observation results of base current, electric field change and optical image, following model of bi-directional leader development for this triggered positive discharge has been figured out. After the rocket reaches a height of a few hundred meters, a downward positive leader firstly initiated from the lower end of the wire attached to the rocket. A few microseconds later, a negative leader intiated at the up end of the same wire and propagating upward. When the downward positive leader going down and connecting with a wire grounded, a pulsating discharge occurred. In addition, a classical positive triggered lightning was also succeeded and the current associating with the upward negative leader in this discharge was observed directly.