  The influence of the Madden Julian Oscillation (MJO) on the precipitation
extremes in Indonesia during the rainy season (October to April) has been
evaluated using the daily station rain gauge data and the gridded Asian
Precipitation Highly Resolved Observational Data Integration Toward Evaluation
of Water Resources (APHRODITE) from 1987 to 2017 for different phases of the
MJO. The results show that MJO significantly modulates the frequency of extreme
precipitation events in Indonesia, with the magnitude of the impact varying
across regions. Specifically, the convectively active (suppressed) MJO
increases (decreases) the probability of extreme precipitation events over the
western and central parts of Indonesia by up to 70% (40%). In the eastern part
of Indonesia, MJO increases (decreases) extreme precipitation probability by up
to 50% (40%). We attribute the differences in the probability of extreme
precipitation events to the changes in the horizontal moisture flux convergence
induced by MJO. The results indicate that the MJO provides the source of
predictability of daily extreme precipitation in Indonesia.
