Interconnection between the Indian and the East Asian summer monsoon: Spatial synchronization patterns of extreme rainfall events

A deeper understanding of the intricate relationship between the two components of the Asian summer monsoon (ASM)-the Indian summer monsoon (ISM) and the East Asian summer monsoon (EASM)-is crucial to improve the subseasonal forecasting of extreme precipitation events. Using an innovative complex network-based approach, we identify two dominant synchronization pathways between ISM and EASM-a southern mode between the Arabian Sea and southeastern China occurring in June, and a northern mode between the core ISM zone and northern China which peaks in July-and their associated large-scale atmospheric circulation patterns. Furthermore, we discover that certain phases of the Madden-Julian oscillation and the lower frequency mode of the boreal summer intraseasonal oscillation (BSISO) seem to favour the overall synchronization of extreme rainfall events between ISM and EASM while the higher-frequency mode of the BSISO is likely to support the shifting between the modes of ISM-EASM connection.

Automated summary

A deeper understanding of the relationship between the Indian summer monsoon (ISM) and the East Asian summer monsoon (EASM) is important for improving subseasonal forecasting of extreme precipitation events. Using a complex network approach, two dominant synchronization pathways and associated atmospheric circulation patterns between ISM and EASM are identified. Additionally, certain phases of the Madden-Julian oscillation and the boreal summer intraseasonal oscillation are found to influence the synchronization of extreme rainfall events between ISM and EASM.