Research On Electric Activity Features Of Severe Convection Weather Process In Jiangsu Area

At present, thunderstorm monitoring is based on satellite cloud pictures, Doppler weather radar data, and observational data on the ground. As an independent detecting parameter, lightning positioning data is of great importance to promote the level of thunderstorm monitoring if it is effectively used. But so far, most researching results about atmospheric electric activity during severe convection weather process are confined to a single sample. The number of samples selected is small and the researching results are lack of representation. According to the condition, this paper selects several samples of severe convection weather process in Jiangsu area and analyzes their electric activity features.The paper introduces lightning production mechanism and its physical effect, the traditional protecting methods and their shortcomings; the physical basis and technical algorithm of lightning position finder to detect thunderstorm; several products of Doppler weather radar such as composite reflectivity (CR), echo tops, storm relative mean radial velocity (SRM), and storm structures.Through the observational data on the ground, nine severe convection weather process samples are selected in Jiangsu area from April to June, 2006. This paper has analyzed their electric activity features by taking the Doppler radar products as the reference. Through statistic analysis, we discover that severe convection weather process in Jiangsu area has obvious characteristics: Positive CG lightning in vigorous stage account for 45.80% to 89.55% of total number of positive CG lightning. Negative CG lightning in vigorous stage account for 64.32% to 93.81% of total number of negative CG lightning. Quantity of positive and negative CG lightning in vigorous stage of thundstorm cloud is obviously higher than in initial stage and dissipated stage. Ratios of positive and negative CG lightning in initial stage , vigorous stage and dissipated stage of thundstorms are respectively from 2.46% to 20.64%, from 1.35% to 8.43%, from 2.83% to 12.8%. CG lightning with high current amplitude (>40KA) in vigorous stage account for 61.94% of total number of CG lightning with high current amplitude in whole process. Positive CG lightning with high current amplitude account for 76.59% of total number of CG lightning with high current amplitude. Quantity of positive CG lightning with high current amplitude is obviously more than negative CG lightning with high current amplitude. Numerical of statistical results and its changing trend can be used to judge the severe convection weather processes.Several samples of severe convection weather process in local area of Jiangsu were selected in this paper. So the electric activity features analyzed from these samples are stable and reliable, and they will be helpful for judging severe convection weather processes.