Quantitative reconstruction of the East Asian Winter Monsoon evolution over the past 100 years: Evidence from high- resolution sedimentary records of the inner continental shelf of the East China Sea

摘要

The East Asian Monsoon (EAM) is a regional factor affecting the East Asian climate and the oceanographic processes of the marginal seas along the Western Pacific. Finding proxies for the EAM intensity and reconstructing the interannual and interdecadal variations of the EAM using high-resolution records are necessary to improve our understanding of the EAM's role in the global climate system and for predicting climate change. In this paper, high-resolution sedimentary records of sedimentary core C0702 obtained from the inner continental shelf of the East China Sea were comprehensively analyzed using a laser particle size analyzer, an Itrax(TM) core scanner, and a Pb-210 and Cs-137 radionuclide analyzer to explore potential proxies for the East Asian Winter Monsoon (EAWM). By combining the obtained results with instrumental observations of the EAM, we established a quantitative formula for the EAWM, which enables to reconstruct the evolution trend of the EAWM during the past 130 years. The sensitive grain-size component F2, with a grain-size range of 14.35-230 mu m, and principal component PC1 of the sedimentary deposits of the East China Sea inner shelf can be used as EAWM proxies. The evolution of EAWM in 1880-1950 could be roughly divided into two stages: a weak EAWM period from 1882 to 1900 and a strong EAWM period from 1900 to 1945. This study improves our understanding of the variations in the EAWM on interannual and interdecadal temporal scales.