Increased effective radiative forcing enhanced the modulating effect of Pacific Decadal Oscillation on late Little Ice Age precipitation in the Jiang-Huai region, China

Research on the evolution and driving mechanisms of East Asian monsoon (EAM) precipitation during the past millennium has received considerable attention. Previous studies have focused on comparisons between relative mean dry/wet conditions and those linked to the Pacific sea surface temperature (SST) anomalies during the Medieval Warm Period (MWP) and the Little Ice Age (LIA); however, uncertainties remain regarding the relationship between precipitation changes and Pacific SST anomalies under sub-cool internal conditions within the LIA. Herein, we present a composite high-resolution monsoon precipitation record (from 1400 CE to the present) based on chroma and median grain size data from Lake Nvshan sediments in the Jiang-Huai (JH) region, central eastern China. The results indicate that more (less) precipitation in the JH region could be associated with the warm (cold) Pacific Decadal Oscillation (PDO) phase on inter-decadal scales. We also observed an enhanced modulating effect of the PDO on JH precipitation during the late LIA. These changes in the modulating effect were likely a response to enhanced PDO amplitudes induced by increased effective radiative forcing.