Abstract

The precipitation regime in the Maritime continent is largely driven by changes in sea surface temperature (SST) in the Pacific and Indian Oceans. The SST anomalies induced by the cycles of Pacific Decadal Oscillation (PDO) and El Niño–Southern Oscillation (ENSO) have a large impact on precipitation regime in the Maritime Continent. Based on long-term observational datasets, this study demonstrates that in-phase occurrence of ENSO and PDO creates a statistically different pattern of precipitation and SST anomalies compared to ENSO cycle accompanied by neutral PDO. The results show that in-phase positive events produce weaker dry anomalies, especially in SON when the amount of precipitation increases by 5-12% of the seasonal norm. In-phase negative events produce stronger dry anomalies in JJA and SON with the amount of precipitation increasing by 3-12% of the seasonal norm relative to ENSO event with neutral PDO. The ENSO-PDO modulation effect leads to rapid changes in precipitation regime in the Maritime continent associated with PDO phase change. Understanding the role of the PDO cycle in the precipitation regime can improve estimates of precipitation trends and lead to better climate change projections.