Collaborative Research: Bioclimatic Reconstruction of the Past 50,000 Years from Eolian Sequences in the Westerlies-Dominated Central Asia

这项研究旨在基于对几个厚风沙剖面的多代理研究，重建西风带主导的中亚地区过去50,000年来详细的生物气候历史。西风带占主导地位的地区包括准噶尔盆地(新疆西北部)和哈萨克斯坦丘陵和平原(哈萨克斯坦东部)，这标志着东亚季风和西风带占主导地位的“欧洲”气候系统的交汇。这项调查将从一套跨越过去5万年的黄土/古土壤剖面中产生古气候替代记录。在重建过程中将使用地球物理、地球化学和地球生物学指标的组合。将沿着三个N-S样带产生基于花粉、蜗牛、有机质碳-13和环境磁参数的生物气候传递函数，以提供过去5万年来生物气候变化的区域覆盖。从研究区域的风成序列对生物气候变化进行相对高分辨率的重建，将为理解过去50 000年来半球和全球尺度的强迫机制和海洋-大气-大陆耦合提供背景。生物气候重建不仅可以更好地了解东亚季风和西风带之间的相互作用历史，而且可以更好地了解北大西洋涛动(NAO)和太平洋北美涛动(PNA)之间的遥相关关系。这项研究的结果将提高对陆地-空气耦合反馈机制的理解，并验证大气气溶胶流入可能引发全球大气CO2变化的假设。该项目将通过建立国际机构(美国、哈萨克斯坦和中国)之间的合作，加强全球气溶胶研究网络中的伙伴关系可能性，重建的生物气候历史将为抗击中亚目前人类加剧的荒漠化问题提供洞察力。

This study aims to reconstruct a detailed bioclimatic history of the last 50,000 years in the westerlies-dominated Central Asia based on a multi-proxy study of several thick eolian sections. The westerlies-dominated region includes the Dzungaria Basin (northwestern Xinjiang) and the Kazakhstan Hills and Plains (eastern Kazakhstan) that mark the conjunction between the East Asian Monsoon and the westerlies-dominated "European" climate systems. This investigation will produce paleoclimatic proxy records from a suite of loess/paleosol sections that span the past 50,000 years. A combination of geophysical, geochemical, and geobiological proxies will be used in the reconstruction. Bioclimatic transfer functions based on pollen, snails, carbon-13 of organic matter, and environmental magnetic parameters will be produced along three N-S transects to provide regional coverage of bioclimatic changes during the past 50,000 years. A relatively high-resolution reconstruction of bioclimatic changes from eolian sequences in the study area shall provide a context for understanding hemispheric- and global-scale forcing mechanisms and ocean-atmosphere-continent couplings throughout the past 50,000 years. The bioclimatic reconstruction will permit a better understanding of not only the interacting history between the East Asian monsoons and the westerlies but also the teleconnections between the North Atlantic Oscillation (NAO) and the Pacific North American (PNA) Oscillation. The outcomes of this research will improve understanding of the land-air coupled feedback mechanisms and validate the hypothesis that atmospheric aerosol influx might have triggered global atmospheric CO2 changes. This project will enhance partnership possibilities in a global network of aerosol studies by establishing collaborations among international institutions (U.S., Kazakhstan, and China) and the reconstructed bioclimatic history will provide insight for combating the ongoing problem of human-exacerbated desertification in Central Asia.