Cloud-to-Ground Lightning Activity over Land and Ocean in Peninsular Malaysia

This paper presents an investigation on the characteristics of cloud-to-ground (CG) lightning over land and ocean in Peninsular Malaysia. The study aims to investigate the characteristics of negative and positive CG in Peninsular Malaysia, particularly over land and ocean on the west coast region and over the Malacca Straits. By analyzing 2020 lightning data recorded by the lightning locating system (LLS) operated by TNB Research (TNBR), we analyzed the negative and positive CG in terms of their occurrences, stroke density, and the peak currents. Six circular regions with a 15 km radius were selected: three (3) over the land and three (3) over the ocean, each having distinct characteristics from the others. We found that most of the CG lightning occurred over land than ocean but there is only a slight difference of 2.4% between the two. We also found that the average peak current for negative CG is higher over the ocean with a geometric mean of 25.7 kA whereas for land, the average value is 21.9 kA. For positive CG, we found that the average peak current is also higher over the ocean with a geometric mean of 32.3 kA whereas for land, the average value is 28.7 kA. The higher occurrence of the CG lightning over land could be due to the heat effect caused by the increase in the development over the land region. The higher intensity of the CG peak currents over the ocean could be due to larger aerosol emission in the area and the higher conductivity of the seawater.