Multiscale Atmospheric Dynamics of Extreme Rainfall Triggering Floods in Bali on 10 September 2025
DOI:
https://doi.org/10.63581/JoCPES.v6i1.05Keywords:
Multiscale Atmospheric Dynamics, Extreme Rainfall, BaliAbstract
This study investigates the multiscale atmospheric dynamics associated with an extreme rainfall event that triggered flooding in Bali on 10 September 2025. A quantitative descriptive approach was applied using ONI, DMI, RMM index, ERA5 reanalysis, Himawari-8 satellite data, and BMKG rainfall observations. Results show that ENSO and IOD were in neutral phases, while the Madden–Julian Oscillation (MJO) was active (RMM amplitude >1), significantly enhancing convective activity over the Maritime Continent. At the regional scale, positive SST anomalies (+0.5–1.5°C), low-level convergence, and strong moisture transport supported upward motion. Local analysis revealed deep convective clouds with cloud-top temperatures below −60°C and rainfall exceeding 100 mm/day. Instability indices showed high K-Index (>35) and moderate CAPE (≈466 J/kg), indicating convection driven by dynamic forcing rather than thermodynamic instability. These findings highlight the dominant role of intraseasonal variability and multiscale interactions in triggering extreme rainfall events in Bali.
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