Cong Zhiyuan, Kawamura Kimitaka, Kang Shichang, Fu Pingqing
1] Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China [2] Institute of Low Temperature Science, Hokkaido University, Sapporo. 060-0819, Japan [3] CAS Center for Excellence in Tibetan Plateau Earth Sciences, Beijing 100101, China.
Institute of Low Temperature Science, Hokkaido University, Sapporo. 060-0819, Japan.
Sci Rep. 2015 Apr 9;5:9580. doi: 10.1038/srep09580.
High levels of carbonaceous aerosol exist over South Asia, the area adjacent to the Himalayas and Tibetan Plateau. Little is known about if they can be transported across the Himalayas, and as far inland as the Tibetan Plateau. As important constituents of aerosols, organic acids have been recognized as unique fingerprints to identify the atmospheric process. Here we measured dicarboxylic acids and related compounds in aerosols on the northern slope of Mt. Everest (Qomolangma, 4276 m a.s.l.). Strong positive correlations were observed for dicarboxylic acids with biomass burning tracers, levoglucosan and K(+), demonstrating that this area was evidently affected by biomass burning. The seasonal variation pattern of dicarboxylic acids is consistent with OC and EC, being characterized by a pronounced maximum in the pre-monsoon season. Molecular distributions of dicarboxylic acids and related compounds (malonic acid/succinic acid, maleic acid/fumaric acid) further support this finding. We suggest that the local meteorological conditions and regional atmospheric flow process could facilitate the penetration of the carbonaceous aerosols from South Asia throughout the Himalayas. With the consideration of the darkening force of carbonaceous aerosols, our finding has important implication for this climate-sensitive area, where the glacier melting supplies water for billions of people downstream.
南亚、喜马拉雅山脉和青藏高原附近地区存在高浓度的碳质气溶胶。关于它们是否能够穿越喜马拉雅山脉并深入内陆到达青藏高原，人们所知甚少。作为气溶胶的重要成分，有机酸已被视为识别大气过程的独特指纹。在此，我们测量了珠穆朗玛峰北坡（海拔4276米）气溶胶中的二元羧酸及相关化合物。二元羧酸与生物质燃烧示踪剂左旋葡聚糖和钾离子呈现出强烈的正相关，表明该地区明显受到生物质燃烧的影响。二元羧酸的季节变化模式与有机碳和元素碳一致，其特征是在季风前季节出现明显的最大值。二元羧酸及相关化合物（丙二酸/琥珀酸、马来酸/富马酸）的分子分布进一步支持了这一发现。我们认为，当地的气象条件和区域大气流动过程可能有助于南亚的碳质气溶胶穿透整个喜马拉雅山脉。考虑到碳质气溶胶的致暗作用，我们的发现对于这个气候敏感地区具有重要意义，该地区的冰川融化是下游数十亿人口的水源。
