High resolution unsaturated alkenones sea surface temperature records in the Yellow Sea during the period of 3500-1300Â cal. yr BP

High-resolution sea surface temperature records based on long-chain unsaturated alkenones (U37K′-SST) in the south Yellow Sea (YS) during the period of 3500-1300 cal. yr BP were reconstructed in sediment core Z8 from the Shandong mud wedge. The SST records show broad variations between 14.3 and 16.9 °C (15.6 °C on the average), with a high SST phase at 3500-2750 cal. yr BP, a low and intense fluctuating SST period at 2500-2000 cal. yr BP and a sharp cooling period at 1750-1300 cal. yr BP. Superimposed on this trend, five cooling periods occurred in 3360-3250 cal. yr BP, 3150-3050 cal. yr BP, 2750-2650 cal. yr BP, 2350-2150 cal. yr BP, and 1750-1300 cal. yr BP. Variation pattern of the SST records is similar to the fluctuations of the Kuroshio Current (KC), indicating a close relationship between the Yellow Sea Warm Current (YSWC) and the KC. The general U37K′-SST curve fluctuates with the local air temperature variations. The intensity of the East Asia Winter Monsoon (EAWM) could be a key factor affected the prevailing relationship between the cold coastal current and the warm YSWC, and dominated the SST variation in core site Z8 during 3500-1300 cal. yr BP. Furthermore, our temperature records, within age uncertainty, coincides with the changes of the solar irradiance changes, suggesting a possible link between solar forcing and climate variability.