A millennial-scale U37K′ sea-surface temperature record from the South China Sea (8°N) over the last 150 kyr: Monsoon and sea-level influence

We report 150 kyr records of U37′ sea-surface temperature (SST) and carbonate content with 150–200-year sampling resolution from the southern South China Sea (SCS) in the northern margin of the Western Pacific Warm Pool (WPWP) using IMAGES Core MD972151. The glacial/interglacial SST change is about 5 °C for Termination II (23.5 to 28.5 °C) and 4 °C for Termination I (24 to 28 °C). The simultaneous rise of sea level and U37′ SST during Termination I suggests that sea-level change has played an important role in the SCS SST variability by influencing the exchange of tropical ocean warm surface water with the SCS through the Sunda Shelf region (sill depth 30–50 m). When sea-level drop was less than 30 m relative to today's, MD972151 SST was constantly above 27 °C, a situation which occurred during MIS 5e, part of MIS5c and 5a, and over the last 11 kyr. Sea-level change was also the main control on carbonate content in the SCS; this was lower during low sea-level stands due to the dilution effect of enhanced terrigenous inputs. Within the limitations of our age model, millennial-scale SST oscillations (1.5 °C over a few hundred years) occurred frequently during the entire glacial period, correlating reasonably well with the Hulu monsoon record from eastern China and the Dansgaard-Oeschger (D-O) cycles recorded for high-latitude regions in the Northern Hemisphere. Such correlations suggest a possible teleconnection between higher latitude atmospheric forcing and low-latitude climate oscillations in the western Pacific tropical region via the Asian monsoon system. Carbonate content also reveals millennial-scale oscillations during the glacial period, with higher content correlated with higher SST. Millennial-scale fluctuations of SST and carbonate contents at this low-latitude SCS provide additional evidence that high-frequency climate changes are global phenomena.