Cao Shan-Shan, Duan Yu-Sen, Gao Chan-Chan, Su Ling, Yang Yi-Xuan, Zhang Yang, Cai Chao-Lin, Liu Min
Shanghai Key Laboratory for Urban Ecological Processes and Eco-restoration, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China.
Shanghai Environmental Monitoring Center, Shanghai 200235, China.
Huan Jing Ke Xue. 2021 Jun 8;42(6):2668-2678. doi: 10.13227/j.hjkx.202009217.
As an important component of atmospheric aerosols, black carbon (BC) has a great influence on the regional and global radiation balance, climate, and human health due to its small particle size, large specific surface area, and radiative forcing potential. Here, the spatio-temporal characteristics of atmospheric BC were investigated based on modern-era retrospective analysis for research and applications version 2 (MERRA-2) reanalysis data and ground observation data during 1980-2019 in Shanghai, a highly urbanized city in mainland China. The influences of local emissions and regional transmission on regional-scale BC concentrations were examined using the M-K trend test, backward trajectory analysis, and the potential source contribution function (PSCF). The results showed that:① MERRA-2 BC and ground observation datasets showed good consistency (∈[0.68, 0.72]), indicating that MERRA-2 reanalysis data can be used to reveal long-term changes in ground-level atmospheric BC concentrations; ② Atmospheric BC concentrations in Shanghai over the past 40 years can be divided into three stages:a "low value" stage of slow growth[1980-1986, (1.75±0.17) μg·m], a relatively stable "median value" stage[1987-1999, (2.18 ±0.07) μg·m], and a fluctuating "high value" stage[2000-2019, (3.07±0.31) μg·m]. Seasonally, Shanghai's BC concentrations generally show a "U" pattern with low concentrations in summer and high concentrations in winter. As a result of black carbon emissions from marine diesel engines and other engines used for water transportation, a small peak also occurs in July; ③ The diagnostic quality ratio of air pollutants and the bivariate correlation analysis[(BC-NO)(BC-CO)(BC-SO)] indicated that traffic emissions were the main sources of atmospheric BC in Shanghai, especially by heavy diesel vehicles; ④ The backward trajectory and PSCF analyses found that the air mass of Shanghai in summer was dominated by a clean sea breeze, accounting for 77.18%. In contrast, during the other seasons, more than 50% of the air mass came from the north. The potential source regions of atmospheric BC in Shanghai are mainly distributed in eastern China, expanding outwards and centering on the Yangtze River Delta, and the expansion direction is consistent with the directions of the backward trajectories.
作为大气气溶胶的重要组成部分，黑碳（BC）因其粒径小、比表面积大以及辐射强迫潜力，对区域和全球辐射平衡、气候及人类健康有着重大影响。在此，基于现代回溯分析研究与应用版本2（MERRA - 2）再分析数据以及1980 - 2019年期间中国大陆高度城市化的上海市的地面观测数据，对大气黑碳的时空特征进行了研究。利用M - K趋势检验、后向轨迹分析以及潜在源贡献函数（PSCF），研究了本地排放和区域传输对区域尺度黑碳浓度的影响。结果表明：①MERRA - 2黑碳数据与地面观测数据集显示出良好的一致性（∈[0.68, 0.72]），表明MERRA - 2再分析数据可用于揭示地面大气黑碳浓度的长期变化；②过去40年上海大气黑碳浓度可分为三个阶段：缓慢增长的“低值”阶段[1980 - 1986年，(1.75±0.17)μg·m]、相对稳定的“中值”阶段[1987 - 1999年，(2.18±0.07)μg·m]以及波动的“高值”阶段[2000 - 2019年，(3.07±0.31)μg·m]。季节性方面，上海的黑碳浓度总体呈现“U”型模式，夏季浓度低，冬季浓度高。由于船用柴油发动机和其他水上运输用发动机排放黑碳，7月也出现一个小峰值；③空气污染物诊断质量比及双变量相关性分析[(BC - NO)(BC - CO)(BC - SO)]表明，交通排放是上海大气黑碳的主要来源，尤其是重型柴油车；④后向轨迹和PSCF分析发现，上海夏季气团以清洁海风为主，占77.18%。相比之下，在其他季节，超过50%的气团来自北方。上海大气黑碳的潜在源区主要分布在中国东部，向外扩展并以长江三角洲为中心，扩展方向与后向轨迹方向一致。
