International Centre for Integrated Mountain Development (ICIMOD), GPO Box 3226, Kathmandu, Nepal; State Key Laboratory of Cryospheric Sciences, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 73000, China; Reading Academy, Nanjing University of Information Science and Technology, Nanjing, Jiangsu, 210044, China; University of Chinese Academy of Sciences, Beijing, China.
International Centre for Integrated Mountain Development (ICIMOD), GPO Box 3226, Kathmandu, Nepal.
Environ Pollut. 2021 Apr 15;275:116544. doi: 10.1016/j.envpol.2021.116544. Epub 2021 Jan 23.
This study discusses year-long (October 2016-September 2017) observations of atmospheric black carbon (BC) mass concentration, its source and sector contributions using a chemical transport model at a high-altitude (28°12'49.21″N, 85°36'33.77″E, 4900 masl) site located near the Yala Glacier in the central Himalayas, Nepal. During a field campaign, fresh snow samples were collected from the surface of the Yala Glacier in May 2017, which were analysed for BC and water-insoluble organic carbon mass concentration in order to estimate the scavenging ratio and surface albedo reduction. The maximum BC mass concentration in the ambient atmosphere (0.73 μg m) was recorded in the pre-monsoon season. The BC and water-insoluble organic carbon analysed from the snow samples were in the range of 96-542 ng g and 152-827 ng g, respectively. The source apportionment study using the absorption Ångström exponent from in situ observations indicated approximately 44% contribution of BC from biomass-burning sources and the remainder from fossil-fuel sources during the entire study period. The source contribution study, using model data sets, indicated ∼14% contribution of BC from open-burning and ∼77% from anthropogenic sources during the study period. Our analysis of regional contributions of BC indicated that the highest contribution was from both Nepal and India combined, followed by China, while the rest was distributed among the nearby countries. The surface snow albedo reduction, estimated by an online model - Snow, Ice, and Aerosol Radiation - was in the range of 0.8-3.8% during the pre-monsoon season. The glacier mass balance analysis suggested that BC contributed to approximately 39% of the total mass loss in the pre-monsoon season.
本研究利用化学输送模型，对尼泊尔喜马拉雅山脉中心的亚拉冰川附近一个高海拔（28°12'49.21″N，85°36'33.77″E，4900 米海拔）站点进行了为期一年（2016 年 10 月至 2017 年 9 月）的大气黑碳（BC）质量浓度观测，以及其来源和部门贡献的研究。在一次实地考察中，于 2017 年 5 月从亚拉冰川表面采集了新鲜雪样，分析了雪样中的 BC 和水不溶性有机碳质量浓度，以估算清除比和表面反照率降低。在季风前季节，环境大气中 BC 的最大质量浓度（0.73μg/m）被记录。从雪样中分析的 BC 和水不溶性有机碳的范围分别为 96-542ng/g 和 152-827ng/g。利用现场观测的吸收 Ångström 指数进行的源分配研究表明，在整个研究期间，BC 中有大约 44%来自生物质燃烧源，其余来自化石燃料源。利用模型数据集进行的源贡献研究表明，在研究期间，BC 中有大约 14%来自露天燃烧，大约 77%来自人为源。我们对 BC 的区域贡献分析表明，来自尼泊尔和印度的贡献最高，其次是中国，其余分布在附近国家。通过在线模型 - Snow, Ice, and Aerosol Radiation - 估算的表面雪反照率降低在季风前季节的范围为 0.8-3.8%。冰川质量平衡分析表明，BC 在季风前季节的总质量损失中约占 39%。
