A New Thunderstorm Identification Algorithm Based on Total Lightning Activity

This paper introduces a new thunderstorm identification algorithm called combinatorial 8-connectivity method based on total lightning activity as observed by the Foshan total lightning location system. The influence of spatio-temporal parameters on the outcome is presented. The evaluation method contains four criteria: the fitting area of lightning clusters, the area proportion of lightning clusters, the number of lightning clusters and the utilization rate of lightning events. It is found that the fitting area adopting grid cells with size 0.02 degrees-0.05 degrees remains constant around 4, 9, 16 and 25 times those using grid cells of 0.01 degrees in size, respectively. The evaluation criteria change by less than 0.61 km(2)/min in area, less than 0.43%/min in area proportion, less than 1/min in number and less than 2.8% in utilization rate using 0.01 degrees grid cell when the duration of time interval exceeds 6 min and the spatial gap between grid cells with lightning events is more than 2 gaps. Then, the evaluation results of the combined 8-connectivity method are compared with the results of the connected-component labeling method (8, 24, 48, 80 and 120-connectivity method), and it is found that the performance of combined 8-connectivity method is better to outline lightning cluster. The two methods have been applied to case analysis on 15 May 2014.

Automated summary

This paper introduces a new thunderstorm identification algorithm based on total lightning activity and analyzes the influence of spatio-temporal parameters. The evaluation method includes four criteria: fitting area, area proportion, number, and utilization rate. Experimental results demonstrate that the combined 8-connectivity method outlines lightning clusters better.