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

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.