[A-CG45] AsiaPEX field campaign strategies for changing Asian monsoon precipitation

[ACG45-03] Intraseasonal and diurnal variations of lightning activities over the coastal heavy rainfall region of Sumatra during the YMC campaign observation periods (2015/2017)

*浜田 純一^1,2、森 修一²、レスタリ ソフィア^3,4、スリストヨワティ レニ³、シャムスディン ファドリ³ (1.東京都立大学都市環境学部、2.国立研究開発法人海洋研究開発機構、3.インドネシア国立研究革新庁、4.名古屋大学宇宙地球環境研究所)

キーワード：海大陸、雷、日変化、MJO

The Indonesian maritime continent is known to be one of the most active regions of the convection and lightning activities. In recent years, diurnal and intraseasonal variations of lightning activity in the maritime continent have been investigated by using World Wide Lightning Location Network (WWLLN) data of the University of Washington. This study aims to show the characteristics of intraseasonal variations, including diurnal variations, in the occurrence of thunderstorms in the coastal heavy rainfall area of Sumatra during the YMC intensive observation periods in 2015 and 2017 (Pre-YMC2015 and YMC-Sumatra2017). It also aims to show the relationship between the thunderstorm occurrence environment and the MJO phase.

The observation results show that there was no significant difference in rainfall amount (daily average) between the El Niño (2015) year and the La Niña year (2017), but there was a large difference in the diurnal variation of rainfall, lightning frequency (lightning activity was high in 2015 and low in 2017), and the response of lightning activity to active/inactive MJO phases. During the inactive phase of the MJO in 2015, lightning became more active, convective clouds developed and reached at altitudes of 10 to 15 km during the daytime, and strong offshore vertical wind shear was observed.