中国西部雪冰溶解性有机质时空变化特征、来源以及气候环境意义

In general, organic matter (OM) dominates the chemical contents in snow/ice, and its physical and chemical properties are more active and rich comparing with inorganic species. More recently, with the improvement of instrument technology and interdisciplinary efforts, the studies of organic matter trapped in snow/ice have aroused increased concern. Because the composition of OM can provide useful information on the source and source regions, the studies for OM in snow/ice are potentially important to better understand the past changes in atmospheric composition. This project will perform a widely collection of snow/ice samples (snow pit and ice core) in the mountain areas of West China (such as Tibetan Plateau) and focus on the temporal and spatial variation of OM, the relationship between OM and inorganic species, the source, transportation, and deposition of OM, and the potential paleo-climate and paleo-environmental index. The methodology of this project will combine the bottom-up and top-down methods and analyze a set of OM compounds and bulk information of OM which will be used to obtain the information of chemical processes and spatial heterogeneity of OM. Especially, an Aerodyne high resolution time-of-flight aerosol mass spectrometer (HR-AMS) was used to chemically characterize the dissolved organic and inorganic matter (DOM and DIM) in snow samples. The HR-AMS analysis will allow obtaining the atomic ratios of oxygen (O), carbon (C), hydrogen (H), nitrogen (N) and sulfur (S) in OM which can get the chemical information of OM, such as oxidation degree, volatility. This project will promote the chemistry research in snow/ice and the frontier science research in this region.

有机质是雪冰中重要的组成成分，其理化性质较无机组分更为活跃和丰富；近些年，随着实验技术和学科交叉的发展，雪冰中有机质的研究在国际上逐渐受到关注，而中国西部雪冰中有机质的研究目前开展较少。本项目将通过大范围采集中国西部山地冰川上的雪冰样品（包括雪坑和冰芯样品，特别是青藏高原地区），开展雪冰中有机质的时空变化特征、有机质来源和大气化学过程，以及有机质对历史气候环境信息记录等研究，关注青藏高原南北气候环境差异等科学问题。有机质的分析方法采用bottom-up（获得某些特征有机物）和top-down（全样有机物）相结合的思路，申请课题中使用的主要分析方法为目前较为先进的气溶胶质谱仪，通过耦合雾化系统，使得气溶胶质谱仪可以开展离线样品的分析，获取雪冰样品中溶解性有机质离子碎片信息，进而获得有机质浓度、元素比率等内容。本项目将有助于丰富雪冰化学的研究内容和推动该地区前沿科学问题的研究。