Eolian dust activity during the last similar to 850 years on the southeastern margin of the arid Central Asia
Eolian dust activity during the last similar to 850 years on the southeastern margin of the arid Central Asia
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干旱中亚东南缘近850年来的风尘活动
DOI：
10.1016/j.palaeo.2020.110022
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Zhang Pu
中科院分区：
文献类型：
--
作者：
Wu Xudong;Li Xiangzhong;Li Junfeng;Wang Min;Ji Ming;Cao Yunning;Hu Jing;Zhang Pu
中亚干旱地区是世界上最大的沙尘源之一，其风沙活动研究对全球气候系统具有重要意义。粒度分布可以提供沉积物来源、搬运过程和沉积环境等信息。因此，GSD是利用湖泊沉积物重建ACA过去风沙活动最常用的指标。利用青藏高原东北部Kuhai湖近850年的GSD数据，用端元分析（end-member analysis， EMA）重建了青藏高原东南缘过去的风沙活动。结果表明，em2和em3分别代表近端风沙悬浮荷载和近端风沙跃迁荷载，构成风沙活动指标。em的分数丰度表明，研究岩心中的硅塑性物质主要来自风成物的贡献。小冰期风沙活动的增强，以及em2和em3的gds表明，近千年来，东亚东南缘风沙活动基本受西伯利亚高产亚洲冬季风的支配。在年代际至百年尺度上，风沙活动的增强通常与太阳总辐照度（TSI）高的暖期相对应。高TSI导致的温度升高将导致蒸发量的增加大于降水的增加，从而导致植被覆盖的恶化和粉尘源的增加。
Eolian dust activity studies on the arid Central Asia (ACA), one of the world's largest dust sources, are of great importance to the global climatic system. Grain size distributions (GSDs) can provide information on sediment sources, transport processes and sedimentary environments. As a result, GSD is the most frequently applied proxy in reconstruction of past eolian dust activities of the ACA using lake sediments. The GSD dataset for a core spanning the last ~850 years from Kuhai Lake on the northeastern Tibetan Plateau was unmixed by end-member analysis (EMA) for reconstruction of past eolian dust activities on the southeastern margin of the ACA. The results suggest that EM 2 and EM 3, which were added together to form an eolian dust activity proxy, represent the proximal eolian suspension and saltation loads, respectively. The fractional abundances of EMs suggest that siliciclastic materials in the studied core were mainly from eolian contributions. The occurrence of enhanced eolian dust activities within the cold Little Ice Age period together with the GSDs of EM 2 and EM 3 indicate that eolian dust activities on the southeastern margin of the ACA were basically governed by the Siberian High-produced Asian Winter Monsoon over the last millennium. At decadal to centennial scales, enhanced eolian dust activities generally correspond to warm periods with high total solar irradiance (TSI). Increased temperatures as the result of high TSI would have caused larger increases in evaporation than in precipitation, and hence deteriorated vegetation cover and increased dust sources availability.