长江流域花粉现代过程研究与LGM来古气候定量重建

本项目通过长江流域表土花粉、山间沼泽泥炭地表层沉积物、空气花粉监测、相对花粉产量等现代过程机理分析，探讨花粉-植被-气候关系，利用多种统计方法辨识主控气候因素，进而利用不同统计模型建立现代花粉-植被-气候定量关系模型；对已经获取的新增岩芯样品（上游的山间沼泽泥炭沉积岩芯和下游的巢湖湖泊沉积岩芯）开展高分辨率花粉分析，建立末次冰盛期(LGM) 以来不同区域花粉化石序列及植被演替序列；对新增的2条高分辨率花粉序列进行温度和降水定量重建，并进行不确定性评估与误差分析；与目前广泛使用、可供自由下载的TraCE-21ka模拟结果进行综合分析，并与不同强迫条件的敏感性试验模拟结果进行对比，评估各因子对长江流域不同区域LGM以来气候演化的影响，探究气候变化的区域差异和变化机制。研究结果将为认识东亚季风的演化、现代暖期所处的背景等重要科学问题提供证据，并为关键区域的生态修复提供有价值的参考。

The project is based on modern pollen process analysis of surface soil, mountain peat-swamp surface sediments, air monitoring and relative productivity in the Yangtze river basin. Then we will explore the relationship of pollen - vegetation - climate using various statistical methods to identify main climate factors, and different statistical model is used to establish the modern pollen - quantitative relationship between vegetation and climate models. High-resolution pollen analysis will be conducted on newly acquired core samples (a peat sedimentary core in the upstream of the Yangtze river basin and a sedimentary core from Chaohu lake in the downstream) to establish pollen fossil sequences and vegetation succession sequences since LGM. The temperature and precipitation of the newly added two high-resolution pollen sequences will be reconstructed quantitatively, and uncertainty assessment and error analysis will be performed. The simulation results of trace-21ka, which is widely used and freely available for download, will be comprehensively analyzed and compared with the simulation results of sensitivity test under different forcing conditions, so as to evaluate the influence of various factors on the climate evolution in different regions of the Yangtze river basin since the last glacial maximum(LGM), and explore the regional differences and change mechanism of climate change. The results will provide evidence for understanding the evolution of the East Asian Monsoon, the background of the modern warm period and other important scientific issues, and provide valuable reference for the ecological restoration of key regions.