Millennial-scale sea surface temperatures of the western Arabian Sea between 37–67 ka BP

Abstract

The Asian monsoon system is a crucial part of the global climate system affecting a significant proportion of the world population. Understanding the controls for changes in the monsoon system is crucial for meaningful assessments of future climate change. The Arabian Sea is part of the wider Asian monsoon system and has been studied regarding controls of monsoon variability through time. In this study, we present sea surface temperature (SST) data from 37–67 ka BP from sediment core NIOP 929 from the western Arabian Sea, assessing the importance of Northern/Southern Hemisphere climate change driving monsoon circulation in the Arabian Sea. Earlier work implies a straightforward link between monsoon variation in the Arabian Sea and Northern Hemisphere millennial-scale climate change during glacial periods, as depicted in Greenland ice cores. We present a new millennial-scale Mg/Ca-based sea surface temperature reconstruction based on the planktic foraminifera species Globigerina bulloides and Globigerinoides ruber. We use these data to calculate seasonal sea surface temperatures. The SST data are variable with a maximum short-term change of 8–9 °C. The variations in our SST records appear to be unrelated to change in either hemisphere in a straightforward fashion by not showing a phase-locked relation to millennial-scale change in Greenland or Antarctic ice core records. We discuss these changes in the context of the Arabian Sea potentially being a “melting pot”, with both the Northern Hemisphere and the Southern Hemisphere exerting influence on a seasonal scale.