青藏高原典型冰川表面吸光性物质时空分布及其对冰川消融的影响

Light-absorbing impurities (LAIs, such as black carbon, organic carbon and dust) deposited to the glacier surface can significantly influence the mass- and energy- balance of the cryosphere. The Tibetan Plateau contains a large number of glaceris, considered as an ideal region to study the impact of LAIs on glacier melting. This project intends to observe and collect snow/ice samples from the benchmark glaciers on Tibetan Plateau (controlled by South Asian monsoon and westerlies, respectively). The experiment analysis of snow/ice samples will address the compositions, concentrations, spatial and temporal characteristics of LAIs. Strengthened observation in the field will be employed to investigate the transport, enrichment and elimination processes of the LAIs, and to quantify the impact of LAIs on the albedo and the radiative forcing of the different glacier surface (fresh snow, aged snow, bare ice) during melting season. The results will be further exploited to assess the contributions of LAIs to the glacier melting. The research results are expected to calibrate the simulation data, and intensify our knowledge of the sources and transport of LAIs and their significance on the glacier albedo. The results will be also served as a valuable scientific basis for the forecasting contributions of the LAIs to the glacier melting under the climate warming.

沉降到冰川表面的吸光性物质（如黑碳、有机碳、粉尘等）对冰冻圈物质能量平衡具有重要影响。青藏高原为冰川分布集中区，是开展雪冰吸光性物质对冰川消融影响研究的理想区域。本项目拟选择高原典型冰川区（南亚季风影响区和西风带影响区）进行野外观测与采样，通过分析明确雪冰中吸光性物质的组成特征、含量水平、空间变化与季节差异；基于消融期的野外强化观测与采样，认识吸光性物质在消融期不同冰川以及同一冰川不同表面（新雪区、老雪区、裸冰区）雪冰中的迁移、富集与清除过程，定量分析吸光性物质在上述过程中对雪冰反照率及辐射强迫的影响，进而评估其对不同地区冰川消融的贡献量。本研究获得的资料不但为大气模式模拟的结果提供验证数据，而且有望加深对吸光性物质的来源和迁移转化及其对反照率影响的机理研究，为进一步预测气候变暖背景下吸光性物质对冰川消融的贡献提供科学基础。

沉降到冰川表面的吸光性物质（如黑碳、有机碳、粉尘等）对冰冻圈物质能量平衡具有重要影响。青藏高原为冰川分布集中区，是开展雪冰吸光性物质对冰川消融影响研究的理想区域。本项目通过高原典型冰川区（南亚季风影响区和西风带影响区）进行野外观测与采样，通过分析明确了雪冰中吸光性物质的组成特征、含量水平、空间变化与季节差异，表明黑碳和粉尘等受到源区、传输、以及沉降等过程的影响；基于消融期的野外强化观测与采样，阐明了吸光性物质在消融期同一冰川不同表面（新雪区、老雪区、裸冰区）的富集以及雪坑中的垂直变化，指出由于夏季消融导致的富集作用，使得不同类型雪冰黑碳等吸光性杂质含量相差可达1-2个数量级；利用SNICAR模型以及冰川物质能量模型，定量分析吸光性物质在上述过程中对雪冰反照率及辐射强迫的影响，进而评估其对不同地区冰川消融的贡献量，指出由于黑碳和粉尘的作用，可导致青藏高原及周边地区冰川消融加速月15%，积雪持续天数缩短3-4天。本研究获得的资料不但为大气模式模拟的结果提供验证数据，而且有望加深对吸光性物质的来源和迁移转化及其对反照率影响的机理研究，为进一步预测气候变暖背景下吸光性物质对冰川消融的贡献提供科学基础。基于本项目，发表研究论文21篇，其中SCI论文14篇，部分研究成果被IPCC “Ocean and Cryosphere”特别评估报告所引用。