Characteristics of lightning discharges in Indonesia

An observation of lightning discharges has been carried out on the Java Island (Indonesia), employing a lightning detection network with four magnetic direction finder sensors. Analysis on the collected data revealed high lightning flash density around the Java Island, especially during the rainy season. The highest annual flash density on the Java Island was 16 flashes per km² per year. Lightning discharges around Java exhibits a diurnal variation, where the activity mostly takes place on the island in the afternoon. A smaller peak of activity, especially in the rainy season, takes place in the early morning offshore. The median of the lightning current amplitudes in this area is around 26 kA, close to the result of direct measurement. The analysis also shows that discharges on the sea bring larger currents than those on the land. Storms on the land tend to deliver more number of strokes with higher maximum flash rates in smaller coverage areas than those occur on the sea.