Decadal Variation of the Rainfall Predictability over the Maritime Continent in the Wet Season

Abstract

Maritime Continent (MC) rainfall plays an important role in global climate variability, but its prediction remains extremely challenging. Based on a long-term state-of-the-art hindcast product recently completed by the authors’ group, this work investigates the decadal variation of the MC rainfall predictability in the wet season for the first time. The prediction skills were relatively high before 1940 and after 1980, but relatively low between these years. In a diagnostic analysis of the controlling factors of the decadal variation, the signal strength represented by the variance of the rainfall variability was identified as the dominant factor. Further analysis concluded that the phases of El Niño–Southern Oscillation (ENSO) are the key controlling sources. The MC rainfall was more predictable during periods dominated by El Niño events than during periods dominated by La Niña events because El Niño elicits stronger ocean–atmosphere interactions in the tropics, providing a stronger signal of MC rainfall than La Niña events.