Influence of East Asian cold surges on tropical precipitation over the Maritime continent

Cold surges are typical weather phenomena of the East Asian winter monsoon and can substantially influence tropical precipitation from the South China Sea (SCS) across the Maritime Continent (MC). This study proposes a revised definition of cold surge events by merging intermittent surges separated by brief (1–2 day) interruptions into continuous episodes. It then classifies cold surge events from 1980 to 2023 into short- and long-lived categories. Composite and lead–lag analyses show that while cold surges of both categories enhance precipitation over the SCS and MC, long-lived events produce not only more persistent but also more intense rainfall. These prolonged cold surges are characterized by sustained northerly winds, enhanced diabatic heating in the mid- to upper troposphere, and deeper convective development. Thermodynamic analyses reveal that long-lived cold surges are more effective in transporting heat and moisture from mid-latitudes and initiate robust ascent when sea surface temperature (SST) exceeds a convective threshold (∼27 °C). Sea level pressure indices over East Asia and Siberia emerge as robust precursors for cold surge occurrence, leading MC precipitation by several days and offering promise for sub-seasonal prediction. Additionally, long-lived cold surges drive persistent SST cooling over the SCS and East China Sea through enhanced surface fluxes. These results highlight the critical role of coupled tropical–extratropical and ocean–atmosphere interactions in cold surge dynamics and underscore their potential for improving intra-seasonal forecast skill in Southeast Asia.