Runoff reconstruction for the Bailong River from tree rings back to AD 1601, reveals changing hydrological signals of China north–south transition zone

Abstract

We present a runoff reconstruction for the Bailong River based on the composite chronology developed from four sampling sites of Pinus tabulaeformis in the China north–south transition zone. The runoff reconstruction, spanning 1601–2013 CE, was developed by calibrating tree‐ring data with the instrumental runoff record. Runoff reconstruction accounted for 44.3% of the actual runoff variance during the common period 1958–2010 and provided a long‐term perspective on hydrological change in the China north–south transition zone. In the past 413 years, high‐ and low‐runoff years accounted for 15.50% and 15.98%, respectively. Of all the 17 extreme hydrological events, 14 of them are extremely high‐flow years, and 17th century was the wettest period during the past 413 years. The preliminary analysis results show that there is a relationship between our runoff reconstruction and the Atlantic multidecadal oscillation at multidecadal scale. Since the 1990s, runoff in the China north–south transition zone has also seen a significant decrease as a result of dry trends of the source region.