El Niño-Southern Oscillation signals imprinted in stalagmite δ18O from 2005 to 2017

Abstract

El Niño-Southern Oscillation (ENSO) is essential to the annual rainfall in the Pacific Rim, causing frequent floods and droughts in these regions. However, its relationship with precipitation in southeastern China on the interannual timescale remains uncertain. Here we reconstruct an ultra-high-resolution hydroclimate record from 2005AD to 2017AD using 301 sets of δ¹⁸O data, U/Th dates, and annual-layer counting on a stalagmite MG2 from Meiguang Cave, Jiangxi Province, southeastern China. We find that both calcite and precipitation δ¹⁸O records have negative correlations with local rainfall amount, with heavier rainfall correlating with negative excursions of δ¹⁸O, supporting the rainfall amount effects on calcite and precipitation δ¹⁸O signals on the seasonal timescale. On the interannual timescale, La Niña (El Niño) years are followed by positive (negative) rainfall years and decreased (increased) MG2 δ¹⁸O values, and all records have ∼3-year cyclicity. The antiphased correlation of medium coefficiency of the Southern Oscillation Index (SOI) with both precipitation δ¹⁸O and MG2 δ¹⁸O records implies that ENSO could modulate the calcite δ¹⁸O signals in the monsoonal region of China through circulation effects. Therefore, we suggest that changes in cave δ¹⁸O values in China can be controlled by both rainfall amount and circulation effects related with the ENSO activities, which provides a good reference for the paleoclimate studies on short timescales.