Late Holocene paleoclimate reconstruction of northern Taiwan using a multiproxy approach in the Dream Lake sediment core.

To understand the role of the East Asian summer monsoon (EASM) and the East Asian winter monsoon (EAWM) on the hydroclimate in northern Taiwan, a multiproxy study has been conducted. This study aims to achieve its goal by using micro-XRF data of Ti and sulfur (S), carbon isotopic compositions (δ13C) along with elemental concentrations of carbon (C), nitrogen (N) and S, and diatom analyses in the sediment core extracted from the Dream Lake (DL; 25°10′01.9″ N, 121°33′36.0″ E and elevation = 588 m above sea level), northern Taiwan. The radiocarbon dates revealed that the DL core covered the time interval from 4.5 to 0.4 cal kyr BP. The current records revealed wetter phases during 4.5–3.0 cal kyr BP, 2.0–1.7 cal kyr BP, and 1.0–0.4 cal kyr BP, characterized by the dominance of C3 plants in the DL catchment, increased runoff, and higher lake levels. Drier climates observed in the current study during 3.0–2.0 cal kyr BP and 1.7–1.0 cal kyr BP, marked by a reduction in C3 plants, decreased runoff, and lower lake levels. The northern Taiwan climate during the late Holocene was observed to be regulated by the interplay of EASM and EAWM. The wet climate conditions during 4.5–3.0 were due to the La Niña-like conditions, which led to a strong EASM resulting in high precipitation conditions. The dry climate conditions during 3.0–2.0 cal kyr BP have coincided with El Niño-like conditions during 3.0–2.4 cal kyr BP and a subsequently strong EAWM during 2.4–2.0 cal kyr BP. Both situations led to a reduction in precipitation in the region. Unlike the time frame from 4.5 to 3.0 cal kyr BP, wet climate conditions during 2.0–1.7 and 1.0–0.4 cal kyr BP have coincided with weak EAWM conditions, which led to an increase in precipitation in northern Taiwan. The dry climate noticed between 1.7 and 1.0 cal kyr BP appeared to be the impact of both El Niño-like conditions and strong EAWM. [ABSTRACT FROM AUTHOR]