ENSO effect on hydroclimate changes in southeastern China over the past two millennia

Meteorological observations indicate that both natural and anthropogenic forcing contribute to regional drought/flood in the East Asian summer monsoon (EASM) domain. However, spatiotemporal rainfall pattern and its dynamics during natural climatic variability remains unclear. Here we reconstruct a similar to 3 year-resolution EASM precipitation record over the past two millennia, based on 13 Th-230 dates and delta O-18 in a stalagmite from Songya Cave, southeastern China. The delta O-18 sequence shows a long-term decreasing trend, indicating an increasing monsoon precipitation over the past two millennia. A series of centennial-scale fluctuations are superimposed on the long-term trend, with a wetter Little Ice Age than the Medieval Warm Period. The long-term trend and centennial-scale oscillations in EASM rainfall are broadly related to El Nino-Southern Oscillation (ENSO) and Pacific decadal oscillation (PDO) variations, with an increased (decreased) EASM rainfall corresponding to El Nino-like (La Nina-like) conditions and positive (negative) phase of PDO. Comparison of delta O-18 records from Songya and Wanxiang Cave shows an anti-phased spatial rainfall pattern between southeastern and northwestern China. This spatiotemporal rainfall pattern, consistent with the modern observations, is possibly regulated by the ENSO, through changes in the location and strength of the Western Pacific Subtropical High (WPSH). (C) 2022 Elsevier Ltd. All rights reserved.

Automated summary

This study reconstructs the precipitation record of the East Asian summer monsoon (EASM) over the past two millennia based on stalagmite records from Songya Cave in southeastern China. The findings show a long-term increasing trend in monsoon precipitation, with fluctuations on a centennial scale. The variations in EASM rainfall are related to El Nino-Southern Oscillation (ENSO) and Pacific decadal oscillation (PDO), and there is an anti-phased spatial rainfall pattern between southeastern and northwestern China.