East Asian winter monsoon variability over the last glacial cycle: Insights from a latitudinal sea-surface temperature gradient across the South China Sea

Abstract

High-resolution planktonic foraminifer Mg/Ca sea surface temperature (SST) and δ 18O records of IMAGES core MD052896 from the southern South China Sea (SCS) provide a history of East Asian winter monsoon variability over the past 23 kyr. Specifically, we find that the latitudinal SST gradient of the north–south SCS shows promise as a useful proxy of East Asian winter monsoon changes. The ΔSST record of core MD052896 from the southern SCS and ODP site 1145 from the northern SCS documents several positive anomalies indicating East Asia winter monsoon maxima during cold periods of the past 23 kyr, including the H1 and Younger Dryas events. The ΔSST record also indicates that after ∼ 8.5 ka the East Asian winter monsoon strengthened relative to the deglaciation, reaching levels of the last glacial period. Comparison of the SCS ΔSST record with stalagmite δ 18O records suggests that both the East Asian summer and winter monsoons strengthened from the last glacial to the Holocene, and that summer and winter monsoon strength probably are not anti-correlated, at least over the last glacial–interglacial cycle.