Geophysical Research Letters | 2021
Gradually Cooling of the Yellow Sea Warm Current Driven by Tropical Pacific Subsurface Water Temperature Changes Over the Past 5 kyr
Abstract
The Western Pacific Warm Pool (WPWP) constitutes the warmest water masses and thus plays an important role in regulating earth s climate. Instrumental data reveal a gradual warming trend over the last 60 years in the WPWP (Solomon & Newman, 2012), the North Pacific western boundary currents, that is, the Kuroshio Current (Wu et al., 2012), and in the marginal seas of China (S. Park et al., 2011), most likely associated with the increase in greenhouse gas emissions. This motivates us to investigate lowto mid-latitude ocean thermodynamic teleconnection at both centennialand millennial-time scales during the Holocene, which remains poorly understood. Numerous studies have demonstrated that the WPWP water heat content experienced a general scenario of an Early Holocene Thermal Maximum and a gradual decrease thereafter. The general Holocene decreasing trend in temperature is superimposed by multi-centennial-scale changes Abstract The integrated effects of ocean-atmosphere dynamics on the temperature evolution in the western North Pacific marginal seas have remained elusive. In order to study mechanisms controlling southern Yellow Sea (YS) temperature changes, bottom water temperature (BWT) changes were reconstructed for the last 8.8 kyr by using the TEX86 index, which archives temperature signal of the winter season Yellow Sea Warm Current. Our results reveal a series of abrupt multi-centennial to millennial scale BWT changes (∼1°C), superimposed on a gradual long-term cooling (>3°C) trend starting from ∼5 ka to the present. The YS BWT changes are positively correlated with subsurface water temperature changes in the Western Pacific Warm Pool (WPWP). The Western Pacific Warm Pool subsurface water cooling signal was most likely transmitted by the Kuroshio Current into the southern YS, highlighting the role of WPWP in influencing thermodynamics of the extratropical regions during the Holocene.