Vol.:(0123456789) 1 3 Climate Dynamics https://doi.org/10.1007/s00382-020-05159-9 Western Pacifc Ocean infuences on monsoon precipitation in the southwestern Chinese Loess Plateau since the mid‑Holocene Can Zhang 1,2  · Cheng Zhao 1,2  · Zicheng Yu 3,4  · Haixia Zhang 1  · Aifeng Zhou 5  · Xiaojian Zhang 6  · Xiaoping Feng 1  · Xiaoshuang Sun 1  · Ji Shen 1 Received: 25 September 2019 / Accepted: 3 February 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020 Abstract Numerous paleoclimate records on reconstructed monsoon precipitation isotopes (δD p and δ 18 O p ) have been published to infer past hydroclimate changes in Asian monsoon region. However, there are still debates on whether or not these recon- structed δD p or δ 18 O p can represent changes of monsoon precipitation. In this study, we report a ~ 5000 year record of leafwax hydrogen isotope (δD wax ) from a 6.67-m-long sediment core collected in Beilianchi (BLC) Lake in the southwestern Chinese Loess Plateau. Based on analyses of the instrumental precipitation isotopes, precipitation amounts, and moisture sources, we fnd that δD p in the southwestern Chinese Loess Plateau shows distinct negative correlation with amounts of summer (from April to September) monsoon precipitation at inter-annual scales. This is further supported by the observed negative relation between precipitation amounts and regional lake-sediments and speleothems inferred δD p (or δ 18 O p ) values at decadal scales over the past 60 years. Therefore, our reconstructed ~ 35-year resolution monsoon precipitation, inferred from δD wax , reveals a long-term decrease since the mid-Holocene. Superimposed on this trend, there are several multi-centennial to millennial-scale fuctuations for increased monsoon precipitation at 4500–4000 years BP, 2900–2400 years BP and 1200–700 years BP and decreased precipitation at 3900–3000 years BP, 2200–1300 years BP, and 500–0 years BP. Reanalyses of instrumental data and Kiel Climate Model on regional atmosphere circulations show that moisture of this region is mainly derived from the western Pacifc Ocean through the East Asian summer monsoon circulation at inter-annual to inter-decadal, and millennial timescales. We conclude that monsoon rainfall in the southwestern Chinese Loess Plateau is likely connected with changes in sea surface temperatures and migrations of the ITCZ in the western Pacifc Ocean. Keywords Chinese Loess Plateau · EASM · Paleolimnology · Paleoclimate · Precipitation isotope · Mid-Holocene 1 Introduction Asian summer monsoon signifcantly afects the economic prosperity and social development in the most populous region of the world with more than 60% of global popula- tion. The Asian summer monsoon is composed of two sub- systems: Indian summer monsoon (ISM) and East Asian summer monsoon (EASM). The former is a tropical mon- soon system with the moisture mainly derived from the Indian Ocean region (Ding et al. 2018). By contrast, the latter is probably a combination of tropical and subtropi- cal monsoon with more complicated moisture sources, including the tropical moisture from the Bay of Bengal and the South China Sea and the subtropical moisture from the western Pacifc Ocean (Sun et al. 2018; Ding et al. 2018). Furthermore, East Asian monsoon region could be infuenced by the westerly and winter monsoon moisture * Cheng Zhao czhao@niglas.ac.cn 1 State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Science, Nanjing 210008, China 2 CAS Center for Excellence in Quaternary Science and Global Change, Xi’an 710061, China 3 School of Geographical Sciences, Northeast Normal University, Changchun 130000, China 4 Department of Earth and Environment Sciences, Lehigh University, Bethlehem, PA 18015, USA 5 College of Earth and Environment Sciences, Lanzhou University, Lanzhou 730000, China 6 School of Geographic and Oceanographic Sciences, Nanjing University, Nanjing 210023, China