青藏高原雪冰中的左旋葡聚糖及其气候环境意义

碳质气溶胶是全球变化研究中的前沿问题，但目前对其来源、传输及历史变化的认知还很薄弱。左旋葡聚糖作为生物质燃烧的分子示踪物已日渐成熟，成为雪冰化学研究最具潜力的突破点之一。本项目拟利用青藏高原雪冰这一独特环境介质，以左旋葡聚糖为目标分析物，在建立可靠的测试方法基础上，通过分析雪坑、大气气溶胶和降水样品，明确不同气候区左旋葡聚糖沉降的现代过程机制；解析雪冰中左旋葡聚糖与黑碳、溶解有机碳、主要离子等指标的内在关系；利用各拉丹冬冰芯恢复青藏高原左旋葡聚糖近百年来的历史记录；定量区分黑碳的化石燃料燃烧和生物质燃烧来源的贡献；结合气团反向轨迹等手段来揭示其潜在源区，阐明左旋葡聚糖的气候环境意义。最终成果既能拓宽现有青藏高原雪冰化学研究的范畴，也能够为评估人类活动对青藏高原的影响提供科学依据。

Carbonaceous aerosol is a key issue in the climate change research. However, up to now the information on its source, transport process and historical variation is still limited. As a good tracer of biomass burning, levoglucosan is becoming one of the most potential breakthrough points. This project focuses on the levoglucosan in the snow and ice from Tibetan Plateau, which are well considered as unique environmental archives. Specifically, on the basis of reliable analysis method, we plan to determine the chemistry of snow pits, aerosol and wet deposition, to reveal the modern deposition process of levoglucosan in different climate regime, and to elucidate the inherent relationship among levoglucosan, black carbon, organic carbon, and major ions. Furthermore, the historical variation of levoglucosan will be reconstructed using the Geladaindong ice core, with the aim to distinguish the contribution of fossil fuel or biomass burning. Finally, we attempt to reveal the possible source region according to backward air mass trajectories, and illustrate the climate and environmental significance of levoglucosan. The results will broaden the current scope of snow/ice research in Tibetan Plateau, and provide scientific basis for the evaluation of the anthropogenic impacts on Tibetan Plateau.