Southern Hemisphere forcing of South Asian monsoon precipitation over the past 1 million years@en

The orbital-scale timing of South Asian monsoon (SAM) precipitation is poorly understood. Here we combine Mg/Ca measurements (a proxy for the temperature prevailing during calcification) and oxygen isotope (δ18O) analyses of the calcite shells of mixed-layer dwelling planktic foraminifera Globigerinoides sacculifer (present all year round in the Bay of Bengal26) in core NGHP 17 (Ref 27) to generate a unique orbital scale SAM precipitation record for the last ~1 million years.南亚季风（South Asian monsoon, SAM）降水的轨道尺度时序迄今仍未得到充分认知。本研究整合了NGHP 17岩心（参考文献27）中栖息于混合层的浮游有孔虫泡抱球虫（Globigerinoides sacculifer，该物种在孟加拉湾全年均有分布，参考文献26）的方解石壳体的Mg/Ca比值测量数据（作为钙化过程中环境温度的代用指标）与氧同位素（δ¹⁸O）分析结果，据此构建了过去约100万年以来独一无二的南亚季风降水轨道尺度记录。