The Impact of Diurnal Precipitation over Sumatra Island, Indonesia, on Synoptic Disturbances and its Relation to the Madden-Julian Oscillation

The impact of diurnal precipitation over Sumatra Island, the Indonesian Maritime Continent (MC), on synoptic disturbances eastern Indian Ocean is examined using high-resolution rainfall data from Global Satellite Mapping Precipitation project and Japanese 55-year Reanalysis during rainy season September to April for period 2000–2014. When cycle strong, high area observed in afternoon migrates offshore nighttime reaches 500 km off coast average. strong events are followed by development several days, apparent twin straddling equator develop only when convective center Madden–Julian Oscillation (MJO) lies (MJO-IO). Without MJO, mainly south equator. differences locations behaviors active related strength mean horizontal winds lower troposphere. During MJO-IO, intensification northeasterly northern hemisphere blowing into organized MJO convection addition southeasterly southern facilitate formation disturbances. These results suggest that seed arising migration differently depending states Ocean. Furthermore, it shown with tend have longer duration continuing eastward propagation across MC, whereas activities other weaken considerably MC again western Pacific. facilitates smooth intraseasonal MC.