第八届青年地学论坛

The tropical Pacific Ocean plays a significant role in climate change, and the El Niño-Southern Oscillation (ENSO) of Western Pacific Warm Pool (WPWP) has been considered have a closely relationship with extreme climate phenomenon worldwide. However, the evolution of the ENSO-like patterns in the tropical Pacific during glacial cycles since the late Pleistocene remains controversial. In this study, we present geochemical indices and a transient model simulation to explore the ENSO-like evolution during the glacial-interglacial cycles and its driving mechanism. Our results indicate that during the interglacial periods, the WPWP tended to be in modern El Niño-like conditions with relatively decreased precipitation and weakened East Asian Summer Monsoon (EASM). On the contrary, during the glacial periods, the state of the climate was more similar to the modern La Niña-like conditions, with an increasing precipitation and the intensification of EASM in WPWP. Evolutionary spectral analyses showed that the variation of hydrodynamic in WPWP was controlled by the earth’s orbital parameters, which are regulated by ocean circulations. Compared with published data, we find evidence for the expansion of the water masses (LCDW and AAIW) from the Southern Ocean would change the redox conditions, productivity and water upwelling in WPWP, and ultimately influence the ENSO-like conditions through CO₂-related Walker Circulation over glacial-interglacial cycles.
 

Late Pleistocene, El Niño-Southern Oscillation, Western Pacific Warm Pool, Mg/Ca ratio, Southern Ocean, Walker Circulation