Paleoclimate Significance of Reconstructed Rainfall Isotope Changes in Asian Monsoon Region
Cheng Zhao, Jun Cheng, Jingjing Wang, Hong Yan, Chengcheng Leng, Can Zhang, Xiaoping Feng, Weiguo Liu, Xiangdong Yang, Ji Shen
Abstract
Abstract Speleothem oxygen isotope (δ 18 Oc) records have been regarded as a critical reference to study past Asian monsoon variability. However, existing δ 18 Oc records in the Indian monsoon region are fragmented in time coverage and/or sampling resolution since the last deglaciation. Also, the climatic interpretation of δ 18 Oc is still obscure. Here, we report a continuous and centennial‐resolved leaf wax hydrogen isotope (δD wax ) record over the past ∼28 ka from Lugu Lake in Indian‐monsoon influenced southwestern China. Our new record shows striking consistency with the well‐established δ 18 Oc record in East Asian monsoon‐influenced southeastern China, revealing a spatially coherent change and thus a similar physical process in rainfall isotopes in the broader Asian monsoon region. Based on the combination with the TraCE21ka simulation, we propose reconstructed long‐term and millennial‐scale isotope changes could be influenced by the intensity of local convection along the monsoon trough, which extends from the Indian subcontinent across to the Philippines in summer.