Spatial Structure and Potential Drivers of Spring Extreme Precipitation Over the Maritime Continent

Abstract Boreal spring extreme precipitation (SEP) over the Maritime Continent (MC) is of great agricultural and socioeconomic importance to both the MC and the surrounding areas. Numerous studies on potential drivers have focused on tropical signals while overlooking the spatial diversity of the SEP. Utilizing the self‐organizing map approach, the SEP over the MC during 1982–2020 is classified into three distinct spatial structures, encompassing western wet‐eastern dry, overall wet, and western dry‐eastern wet patterns. The western wet‐eastern dry pattern is primarily related to anomalous negative–positive–negative sea surface temperature (SST) over the south of the MC–tropical southwestern Pacific–tropical southeastern Pacific, which results in the vertical motions characterized by a western ascending‐eastern descending pattern in the MC. The overall wet pattern is tightly linked to spring surface sensible heat flux in the Tibetan Plateau (TP), which exhibits a north‐positive and south‐negative spatial structure. Associated with this dipole structure, a pronounced anomalous anticyclone dominates the upper‐level atmosphere over the western TP and India. This system induces significant upper‐level easterly wind anomalies and wind divergence, coupled with lower‐level wind convergence over the MC, thereby producing an overall wet pattern. Finally, the western dry‐eastern wet pattern is highly correlated with the preceding winter La Niña‐like SST pattern, which enhances the SST gradient between the eastern MC–tropical western Pacific and its two sides, resulting in ascending (descending) motions and more (less) rainfall over the eastern (western) MC. By considering both the spatial structures and tropical/extratropical drivers of the SEP over the MC, our finding advances its understanding, thereby providing an essential basis for predicting extreme precipitation in the region.