A half-millennium perspective on recent drying in the eastern Chinese Loess Plateau

Northern China has experienced dramatic drying since the 1960s CE. However, the scarcity of long-term observations hampers the evaluation of recent drought variations from a long-term perspective. Here, we present a tree-ring-width chronology of Chinese pine (Pinus tabuliformis Carr.) from the eastern edge of the Chinese Loess Plateau (ECLP), which is the longest tree-ring chronology on the ECLP (1535-2018 CE). This chronology was used to reconstruct the average April-June self-calibrated Palmer Drought Severity Index (scPDSI). The reconstruction explains 64.3% of the variations in the observed scPDSI during the calibration period (1954-2000 CE). The driest and wettest years over the full reconstruction were 1759 CE and 1649 CE, respectively. The two most prolonged drought intervals occurred in 1892-1943 CE and 1737-1775 CE, while the two most prolonged pluvial intervals occurred in 1950-1992 CE and 1645-1682 CE. The reconstruction captures the recent drying since the 1960s. However, we found that the recent notable drying is not unprecedented over the last half millennium, as more dramatic drought fluctuations occurred around the 1650s-1690s. The spatial correlation with sea surface temperature (SST) indicates that the drought variations on the ECLP might be modulated by the North Atlantic SST tripolar pattern. This study provides a reference for long-term drought evaluation, which may have implications for drought prediction and adaptation on the ECLP.