Novelia Exela, Syafriani, Trismidianto
On October 16–17, 2022, extreme rainfall occurred around East Java and Bali which caused landslides, broken bridges, several deaths, thousands of people being displaced, and significant economic and material losses. It was identified that a mesoscale convective complex (MCC) in East Java and deep convection in Bali were the causes of this extreme rainfall. This study reported that the MCC in East Java triggered deep convective growth and extreme rainfall in Bali. This study used several datasets, namely cloud top temperature (CTT) from Himawari-8, GSMaP rainfall and weather parameters from ECMWF ERA5, and surface winds using CCMP. This study shows that the short-lived MCC caused the extreme rainfall on these 2 days in East Java, but the extreme rainfall in southern Bali was caused by deep convective development triggered by the presence of the MCC. The MCC development was triggered by diurnal variations in East Java from afternoon to midnight. The development of MCC in East Java is due to the meeting of strong surface wind flows with strong surface convergence. The MCC development was also triggered by the presence of the moisture flux convergence (MFC) border front and mounds of moisture around the MCC location. The significant difference in geopotential height in East Java and Bali when the MCC occurred also shows a trough and ridge pattern that will give rise to a jet stream, which is usually associated with stronger MCC development. These MCCs triggered deep convective growth in southern Bali after decay via cold pool outflow, which brought new convective clouds and induced a convective environment. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.
Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Negeri Padang (UNP), West Sumatra, Padang, Indonesia; Research Center for Climate and Atmospheric, National Research and Innovation Agency, Bandung, 40173, Indonesia
