Spatial and temporal variability of sea surface temperatures and monsoon dynamics in the northwestern Arabian Sea during the last 43 kyr

Abstract. In this study, we present the first well-dated, high-resolution alkenone-based sea surface temperature (SST) record (SL167) from the northeastern Oman Margin (Gulf of Oman) in the northwestern Arabian Sea. The SST reconstructions spanning the last 43 kyr reveal fluctuations of approximately 7 °C (20.1 °C to 27.4 °C) and demonstrate a higher sensitivity to climate variations compared to similar core locations in the Arabian Sea. SSTs remained low during Heinrich events (H2, H3, H4), the Younger Dryas, early and late Holocene, and were high during Dansgaard-Oeschger interstadials (D-O 11, D-O 4 - 9, Bølling-Allerød (B-A), and mid-Holocene. SST was predominantly influenced by the SW monsoon during warmer periods and the NE monsoon during cold intervals. The dynamics of strengthening and weakening monsoon periods were likely controlled by shifts in the Intertropical Convergence Zone prompted by changes in solar radiation in the Northern Hemisphere. The last glacial maximum exhibited no intense cooling probably due to stronger NW winds and an eastward shift of the SST gradient in the Gulf of Oman, resulting in a brief and moderate cooling period. Strong SW winds during the early Holocene transported cold water masses from Oman upwelling into the Gulf of Oman, lowering SSTs. A rapid temperature increase of approx. 2 °C during the mid-Holocene was induced by an abrupt eastward shift of the SST gradient.