Western Pacific Ocean influences on monsoon precipitation in the southwestern Chinese Loess Plateau since the mid-Holocene

• Published in: Climate dynamics Vol. 54; no. 5-6; pp. 3121 - 3134
• Main Authors: Zhang, Can, Zhao, Cheng, Yu, Zicheng, Zhang, Haixia, Zhou, Aifeng, Zhang, Xiaojian, Feng, Xiaoping, Sun, Xiaoshuang, Shen, Ji
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.03.2020; Springer; Springer Nature B.V
• Subjects: Analysis; Annual precipitation; Atmospheric circulation; Atmospheric precipitations; Climate; Climate models; Climatology; Earth and Environmental Science; Earth Sciences; East Asian monsoon; Geophysics/Geodesy; Holocene; Hydroclimate; Hydrogen; Hydrogen isotopes; Isotopes; Lake sediments; Lakes; Loess; Moisture; Monsoon circulation; Monsoon precipitation; Monsoon rainfall; Monsoons; Ocean; Oceanography; Oceans; Paleoclimate; Paleogeography; Plateaus; Precipitation; Rain; Rain and rainfall; Rainfall; Regional climates; Sea surface; Sea surface temperature; Sediments; Summer; Summer circulation; Summer monsoon; Surface temperature; Wind; South China Sea; East Asia; China; Pacific Ocean; Loess Plateau; Chinese Loess Plateau; Paleoclimate; Precipitation isotope; Mid-Holocene; EASM; Paleolimnology
• ISSN: 0930-7575; 1432-0894
• DOI: 10.1007/s00382-020-05159-9

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 reconstructed 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 find 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 fluctuations 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 Pacific 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 Pacific Ocean.