A monsoon-related 174-year relative humidity record from tree-ring δ18O in the Yaoshan region, eastern central China

The authors present a time series of tree-ring cellulose stable oxygen isotope ratios (δ18O) constructed using a numerical mixing method, from five Pinus tabulaeformis from Yaoshan, eastern central China. The time series is synchronous with the observed April-to-September precipitation δ18O time series records from surrounding stations, implying that the tree-ring δ18O signals reflect Asian summer monsoon-related precipitation. Moreover, significant correlations were detected between the tree-ring δ18O records and central-eastern Pacific sea surface temperature (SSTs)/Asian summer monsoon indices. This suggests that the Yaoshan tree-ring δ18O time series offers a promising means to study past Asian summer monsoons and ENSO variability. The time series is significantly correlated with the mean relative humidity from April to September (RHAS) (r=-0.638, n=52, p