青藏高原中东部全新世植被演替与气候演变研究

In East Asia, the Tibetan Plateau plays an extremely important role in affecting global climatic change, especially the monsoon system in Asia. The plateau is a high-altitude arid steppe interspersed with mountain ranges and large brackish lakes and it contains the world's third-largest store of ice. As the roof of the world, the plateau is very sensitive to climatic change. Temperatures there are rising four times faster than elsewhere in China, and the Tibetan glaciers are retreating at a higher speed than in any other part of the world. What is happening and will happen to the vegetation in Tibet when the climate changes? This study of climatic change and vegetation succession in the Tibetan Plateau in the Holocene, the past 11,600 years, should give us the answer.In this proposed project, we will study a series of surface soil samples and drilling cores collected from mid-east Qinghai-Tibetan Plateau. The elevation difference of these samples is about 2100 meters (lowest at 3,074 m a.s.l. and highest at 5,186 m a.s.l.). The lengths of the cores are 0.75 to 1.59 m.Based on the palynological assemblages obtained from the drilling cores, we can reconstruct the vegetation succession in the Holocene. Based on the palynological data and published meteorological data, we can obtain the paleoclimatic parameters of these sites of Holocene age by applying the Best Analogs Method. The results of this study will provide the evidence for understanding the response mechanism between the vegetation succession and climate changes on the Tibetan Plateau. To increase the accuracy of the identification of the pollen taxa, the Single Grain Technique will be applied in this research. A further comparison of the results in this study will tell us the internal links of the vegetation, climate and landscape at different elevations on the Tibetan Plateau.

位于青藏高原高海拔地区的草甸、湖泊和冰川对气候变化的响应极为明显。对全新世青藏高原的植被演替和气候变化科学问题的探讨可为全球变化的研究提供关键的资料和数据。本项目拟通过分析青藏高原中东部一系列表土样品及湖泊钻孔样品，以孢粉学为手段研究青藏高原中东部全新世以来的植被演替和气候变化。其中，表土孢粉样品的实验室分析已基本完成,部分湖泊钻孔样品的孢粉分析也已经完成。本项目将开展以下研究工作: 基于气象数据及现生植被资料研究表土孢粉组合与现生植被的内在关系及重要类群的花粉传播机制；综合表土孢粉和湖泊钻孔孢粉的分析结果，结合测年数据，应用最佳类比法获取定量气候参数；在空间尺度和时间尺度上研究青藏高原中东部全新世以来植被和气候的变化。本项研究将揭示青藏高原全新世以来气候演变，以及青藏高原中东部地区气候变化和东亚季风之间的内在联系和耦合机制，为认识亚洲地区的全新世环境和气候变化提供重要的和直接的资料。

作为地球的“第三极”，青藏高原对气候变化的响应极为敏感。随着近年来气候变化问题越来越受到关注，青藏高原相关研究也成为研究热点。利用孢粉数据对青藏高原的植被演替和气候演变进行分析，将有助于我们更好的理解青藏高原对全球气候变化的响应机制。也为全球气候变化研究提供更多的基础参考数据。本项目通过对青藏高原的表土孢粉组合和沉积物孢粉分析，力图揭示数千年来青藏高原的植被与气候对全球气候变化的响应过程和机制。依托本项目，我们系统采集了南北及东西向贯穿青藏高原约200份表土孢粉样品，并采集了一系列的浅钻。表土孢粉的分析表明，青藏高原表土孢粉散布模式受高原东南部边缘植被影响巨大。本项目利用浅钻沉积物孢粉分析了约两千年来植被和气候的变化。

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