Rapid climate fluctuations over the past millennium: evidence from a lacustrine record of Basomtso Lake, southeastern Tibetan Plateau.

Kai Li,Ulrike Herzschuh,Xingqi Liu,Yongbo Wang

doi:10.1038/srep24806

Abstract

Abrupt climate changes and fluctuations over short time scales are superimposed on long-term climate changes. Understanding rapid climate fluctuations at the decadal time scale over the past millennium will enhance our understanding of patterns of climate variability and aid in forecasting climate changes in the future. In this study, climate changes on the southeastern Tibetan Plateau over the past millennium were determined from a 4.82-m-long sediment core from Basomtso Lake. At the centennial time scale, the Medieval Climate Anomaly (MCA), Little Ice Age (LIA) and Current Warm Period (CWP) are distinct in the Basomtso region. Rapid climate fluctuations inferred from five episodes with higher sediment input and likely warmer conditions, as well as seven episodes with lower sediment input and likely colder conditions, were well preserved in our record. These episodes with higher and lower sediment input are characterized by abrupt climate changes and short time durations. Spectral analysis indicates that the climate variations at the centennial scale on the southeastern Tibetan Plateau are influenced by solar activity during the past millennium.

Highlights

accelerator mass spectrometry (AMS) 14C Age Calibrated age Median age [yr BP with 2σ] Calendar yr 184 ± 18
In view of long-term climate evolution, climate fluctuations exist at different time scales
The organic matter content, grain size and magnetic susceptibility (MS) in Basomtso Lake are sensitive to glacier activities that are directly forced by climate variations

Summary

Introduction

AMS 14C Age Calibrated age Median age (yr BP ± 1σ) [yr BP with 2σ] Calendar yr 184 ± 18. Which is at an elevation of 3000 m a.s.l. and located 65 km southeast of Basomtso Lake. The meteorological station records for 1960–1964 AD and 1973–2012 AD indicate a mean July temperature (TJuly) of 15.9 °C, a mean January temperature (TJan) of 0.9 °C and a mean annual precipitation (Pann) of 1130 mm (90% falling between April and October). The current Jiao-Guoguo and Zhong-Co glaciers are distributed in the Basomtso Lake basin (Fig. 1). Basomtso Lake is mainly fed by glacier melt water via fluvial runoff from the Basom and Nize Rivers and discharges into Yarlung-Tsangpo River through the Ba River and Niyang River[17]

Methods

Results

Conclusion