Analisis Jangka Panjang Propagasi MJO dan Respons Konvektif di Benua Maritim Indonesia (1996–2025)

The characteristics of Madden–Julian Oscillation (MJO) propagation over multi-decadal periods in the Maritime Continent remain relatively understudied, despite the fact that variations in its duration and propagation success may significantly influence long-term convection patterns. This study analyzes MJO propagation during the period 1996–2025 and its impacts on Outgoing Longwave Radiation (OLR) anomalies, wind divergence, and moisture transport using NCEP–NCAR Reanalysis data and the Real-time Multivariate MJO (RMM) index. The analysis employs composite methods by phase, calculations of divergence and moisture flux, and bootstrap significance testing within the domain 7°N–14°S and 95°E–140°E. The results indicate that MJO occurrence frequency was highest during MAM (1,051 days) and DJF (971 days), while the lowest frequency occurs during JJA (513 days). Active MJO phases (phases 4–5) are characterized by negative OLR anomalies reaching −25 W m⁻², strong upper-level divergence at 200 hPa, and low-level convergence accompanied by enhanced moisture transport at 850 hPa, particularly during DJF and MAM. In contrast, phases 1 and 8 show dominance of subsidence conditions with positive OLR anomalies reaching +20 W m⁻². During JJA, the convective response weakens due to modulation by the easterly monsoon, which shifts the convection center north of the equator. Overall, the effectiveness of MJO propagation is controlled by atmospheric vertical coupling, moisture availability, and the background regional monsoon circulation.