High- and low-latitude forcing on the south Yellow Sea surface water temperature variations during the Holocene

Abstract

Abstract Sea surface temperature (SST) of the modern Yellow Sea (YS) is sensitive to forcing by both the East Asian monsoon and the North Pacific western boundary current, however, detailed mechanisms for explaining the Holocene SST evolution remains to be understood. Here we present two decadal sampling resolution alkenone SST records from the south YS spanning the last 8.9 kyr to understand forcing mechanisms on different timescales. The results show that the two sites from the south YS experienced SST variations on millennial timescale, displaying mean high values of 16.5 °C (A03-B) and 15.2 °C (YS01) from 7.7 to 5.9 ka, followed by low values of 16.4 °C (A03-B) and 14.8 °C (YS01) from 5.9 to 2.9 ka, then by high values of 16.9 °C (A03-B) and 15.5 °C (YS01) from 2.9 to 0.6 ka. After the entrance of the YS Warm Current at about 7.5 ka, evolution of the south YS SSTs paralleled the pattern of the main Kuroshio Current intensity, i.e., low (high) SST coeval with weak (strong) Kuroshio Current, suggesting that millennial-scale SST variations in the south YS were primarily controlled by the Kuroshio Current. Superimposing on the millennial variations, seven abrupt centennial-scale cold events were observed during the Holocene, with SST oscillations broadly coeval with those of North Atlantic ice-rafted detritus and East Asian winter monsoon rather than SSTs from the Okinawa Tough and Indo-Pacific warm pool. Hence, we propose that the East Asian winter monsoon was the top-down conveyor transmitting North Atlantic cooling signals to the south YS on centennial timescale. Thus, our study reveals both high- and low-latitude climate forcing on the evolution of the south YS SST during the Holocene, with low-latitude forcing on millennial-scale and high-latitude forcing on centennial-scale.