资源环境科技发展态势分析平台

Lightning data from the World Wide Lightning Location Network for the period 2005-2015 were used to investigate climatic characteristics of lightning activity over the northwest Pacific region (0 degrees-55 degrees N, 100 degrees-180 degrees E). The highest lightning densities (LDs) were observed over the coastal areas of southeast Asia and the tropical islands, which differs significantly from the distribution of the highest precipitation rates. The LD in the South China Sea (SCS) was much higher than that over the deep ocean and showed a peak that was 3 h ahead of that seen in the open sea. A sharp increase in LD on the Indo-China Peninsula and in the SCS was observed during the pre-monsoon season. The monthly variations show that the highest lightning activity occurred during July, August, and September, which is consistent with the variations in the monthly precipitation rate.

The contribution of tropical cyclones (TCs) and the impact of El Nino and La Nina events on lightning climatology over the northwest Pacific region were also examined. Two areas of maximum TC lightning were observed to the east of the Philippines and south of China, indicating that frequent lightning is produced when TCs are approaching landfall. The average LD during El Nino events increases by 10.3%, whereas during La Nina events it decreases by 4.8%. A northward shift in the positive lightning anomaly was observed in the SCS, from the southern SCS during the El Nino to the central and northern SCS during the La Nina periods.