Recurring dipole flooding patterns in East Asia throughout the Holocene

Area of Science:

• Paleoclimatology
• Hydrology
• Climate Dynamics

Background:

• Flood frequency and distribution in eastern monsoon China are poorly understood over the Holocene.
• This region is densely populated, making flood risk management critical.
• Long-term flood patterns are essential for effective disaster mitigation strategies.

Purpose of the Study:

• To reconstruct the history of large floods in the Yellow River and Yangtze River basins during the Holocene.
• To identify spatiotemporal patterns and cyclicity of Holocene floods in eastern monsoon China.
• To investigate the climatic drivers behind observed flood patterns.

Main Methods:

• Reconstruction of large flood history using proxy records from the Yellow and Yangtze River basins.
• Analysis of millennial-scale flood cyclicity across the Holocene.
• Climate model simulations to understand the influence of El Niño, Atlantic Meridional Overturning Circulation (AMOC), and solar activity on flood patterns.

Main Results:

• Clear evidence of a persistent dipole flooding pattern between the northern Yellow River and southern Yangtze River basins.
• A cyclicity of approximately 1.0 ka (1000 years) was identified across the Holocene.
• Yangtze River flooding correlates with enhanced El Niño events modulated by weakening AMOC.
• Yellow River flooding peaks during solar maxima, influenced by a La Niña-like background state.

Conclusions:

• Millennial-scale climate dynamics, including AMOC and solar cycles, significantly influence regional flood patterns in eastern China.
• Future weakening of AMOC may intensify El Niño events, increasing flood risk in southern China.
• Integrating long-term climate dynamics into adaptation strategies is vital for future flood risk management.