Wet deposition of black carbon: A synthesis
Wet deposition of black carbon: A synthesis
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DOI：
10.1016/j.atmosenv.2019.06.033
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发表时间：
2019-09
影响因子：
5
通讯作者：
T. E. Barrett;A. Ponette-González;J. Rindy;K. Weathers
中科院分区：
文献类型：
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作者：
T. E. Barrett;A. Ponette-González;J. Rindy;K. Weathers
黑碳（BC）影响全球辐射收支，对空气质量和人类健康产生不利影响。从大气中去除BC可以减轻这些影响。虽然湿沉降（降雨）被认为是陆地和海洋上去除BC的主要途径，但量化降雨BC浓度和沉降的研究很少。在这里，我们综合了1984年至2016年期间从世界各地的站点进行的降雨中BC的经验测量。收集了来自20种同行评审出版物和42个独特网站的数据。所有观测都来自北方半球，其中绝大多数位于年降雨量中等至较高的中纬度地区。城市，农村和偏远地区之间的降雨BC浓度和沉积的差异进行了研究。年降雨量的BC浓度范围为120倍，从偏远站点的2.8 μg L− 1到城市站点的333 μg L− 1，而年BC沉积量范围为16倍，从偏远站点的0.014 mg m−2d− 1到城市站点的0.22 mg m−2d− 1。少量的观测，高测量变异性，相对于海岸的位置似乎掩盖了土地利用对降雨BC的影响。然而，在具有类似降雨模式、BC排放源和气团轨迹的地理区域，发现了BC浓度和/或沉积的典型季节模式。各站点的年降雨量BC沉积与全球海洋的模拟估计值相当，但BC浓度略高于北美中部站点地表雪中测得的浓度。无论是热带地区还是城市地区（BC排放热点）在数据集中都没有很好的代表性，突出了对降雨BC沉积的理解的根本差距。更广泛地监测降雨BC沉积对于开发改进的全球气候和碳循环模型至关重要。
Black carbon (BC) influences the global radiation budget and adversely affects air quality and human health. Removal of BC from the atmosphere can mitigate these effects. Although wet deposition (rainfall) is thought to be a dominant pathway for BC removal over land and oceans, studies quantifying rainfall BC concentrations and deposition are scarce. Here, we synthesize empirical measurements of BC in rainfall conducted between 1984 and 2016 from sites around the world. Data from 20 peer-reviewed publications and 42 unique sites were compiled. All observations were from the northern hemisphere, with the vast majority located in mid-latitudes with medium to high annual rainfall. Differences in rainfall BC concentrations and deposition among urban, rural, and remote sites were examined. Annual rainfall BC concentrations ranged 120-fold, from 2.8 μg L−1at a remote site to 333 μg L−1at an urban site, while annual BC deposition ranged 16-fold from 0.014 mg m−2d−1at a remote site to 0.22 mg m−2d−1at an urban site. The small number of observations, high measurement variability, and location relative to coast appeared to mask the effects of land use on BC in rainfall. However, characteristic seasonal patterns in BC concentrations and/or deposition were found for geographic regions with similar rainfall patterns, BC emission sources, and air mass trajectories. Annual rainfall BC deposition across sites was comparable to modeled estimates for the global oceans, but BC concentrations were somewhat higher than those measured in surface snow at central North American sites. Neither tropical regions nor urban areas (BC-emission hotspots) were well represented in the dataset, highlighting fundamental gaps in understanding of rainfall BC deposition. More extensive monitoring of rainfall BC deposition is imperative to develop improved global climate and carbon cycling models.