[M-IS02] Evolution and variability of the Asian Monsoon and Indo-Pacific climate during the Cenozoic Era

[MIS02-04] The impact of sea level change on the East Asian Monsoon during the Last Glacial Maximum

*Evan James Gowan¹、Tomohiko Tomita¹、Daiki Nishioka¹、Xu Zhang²、Yong Sun³、Uta Krebs-Kanzow⁴、Gregor Knorr⁴ (1.Kumamoto University, Kumamoto, Japan、2.State Key Laboratory of Tibetan Plateau Earth System, Resources and Environment (TPESRE), Chinese Academy of Sciences (CAS), Beijing, China、3.Key Laboratory of Continental Collision and Plateau Uplift, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, China、4.Alfred Wegener Institute, Bremerhaven, Germany)

キーワード：East Asian Monsoon, Last Glacial Maximum, sea level change, Sea of Japan, paleoclimate

During the Last Glacial Maximum (LGM - 26-19 ka), the climate in eastern Asia, including Japan, was colder and drier. This was primarily the result global cooling from lower CO2 concentrations and low high latitude summer insolation. However, the east Asian monsoon, which drives most precipitation in the region, was also likely affected by local changes in sea level. Due to the growth of continental ice sheets in North America and Europe, sea level fell by over 110 m during the LGM. This caused the subaerial exposure of the East China Sea, and almost completely stopped exchange of Pacific sea water with the Sea of Japan. We present preliminary modelling experiments, using the PaleoMIST topography reconstruction, to quantify and isolate the effect that sea level change had on the east Asian monsoon. In our experiments, we test scenarios for both a preindustrial and LGM climate parameters. In order to quantify the impact of sea level change, we test both scenarios with and without the drop in sea level in Eastern Asia. Early results suggest that over the exposed continental shelf, there is an increase in summer monsoon precipitation during the LGM compared to present, while all other regions are drier. Our modelling results include oxygen isotope tracing, which may help to quantify the relationship between sea level change and low d18O values in the Sea of Japan during the LGM.