Active lightnings during the tropical cyclone genesis over the Philippine Sea

The accuracy of tropical cyclone (TC) track forecast has been improved year by years. On the other hand, the forecast of TC intensity still has a difficulty of improvement. Recently the relationship between lightning activity and TC intensity has been investigated. Lightning tends to increase during the rapid intensification of the TC. Therefore, monitoring the lightning activity becomes important for a TC intensity forecast. Lightning observation network are deployed over the western north Pacific by five very long frequency events trigger measurements called V-POTEKA at Palau, Guam, Manila Philippines, Okinawa Japan and Serpong Indonesia under the ULAT (Understanding Lightning and Thunderstorm) of SATREPS (Science and Technology Research Partnership for Sustainable Development) in the Philippines. Lightning activity was drastically increased around the TC during the TC genesis stage of tropical storm Maysak on 28 August 2020. Numbers of lightning reached the maximum during the life cycle of the TC. Location of lightnings were concentrated near the center of TC within 200 km radius. We called this phenomenon as lightning burst. About 75% of the TCs observed lightning bursts during the TC genesis stage over the Philippine Sea in 2020. Lightning bursts tend to occur when TC generates near the coast of the Philippines. The environment of land-based aerosol will be necessary for more lightnings in the TCs and the lightning bursts. Quality control of lightning measurement of V-POTEKA was conducted by comparing WWLLN (World Wide Lightning Location Network) data. V-POTEKA tends to underestimate lightnings outside the stations array. However, WWLLN data showed consistent lightning bursts during the TC genesis and supported the results.