Spatiotemporal Evolution of Mesoscale Convective Systems (MCSs) and Rainfall Over Citarum River Basin, West Java

Abstract

Mesoscale convective systems (MCSs) are major contributors to extreme rainfall in tropical regions, yet their lifecycle-dependent rainfall characteristics over the Indonesian Maritime Continent remain poorly documented. This study investigates the spatiotemporal evolution of MCSs and associated rainfall over the Citarum River Basin, West Java. We focused on the rainy seasons of 2013–2023, based on  hourly infrared satellite data and IMERG precipitation. The results reveal a pronounced diurnal cycle, and up to 70% MCS events occurred at the afternoon–night period (12–24 LT). MCSs generally start over upstream mountainous areas and propagate toward the central and downstream basin at night, indicating a strong topographic influence. Our findings show that the mature phase of MCS produces the highest intensity and frequency of heavy rainfall (>10 mm h⁻¹), whereas the dissipation phase contributes to persistent stratiform rainfall. Further, we find that most extreme rainfall in the basin is triggered by MCSs. These findings highlight the role of MCS evolution and basin topography in shaping extreme rainfall characteristics and may support improvements in extreme weather monitoring and early warning systems.