| 兰州市冬季气溶胶吸光特性研究——黑碳与棕色碳的区分及特征分析 |
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| 引用本文： | 谢聪慧,徐建中.兰州市冬季气溶胶吸光特性研究——黑碳与棕色碳的区分及特征分析[J].冰川冻土,2017,39(6):1249-1257. |
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| 作者姓名： | 谢聪慧 徐建中 |
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| 作者单位： | 中国科学院 西北生态环境资源研究院 冰冻圈科学国家重点实验室,甘肃 兰州730000;中国科学院大学,北京100049;中国科学院 西北生态环境资源研究院 冰冻圈科学国家重点实验室,甘肃 兰州,730000 |
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| 摘 要： | 为研究兰州市冬季亚微米气溶胶的吸光特性,利用2014年1月10日至2月4日黑碳仪(AE31)和高分辨率飞行时间质谱仪(HR-To F-AMS)观测资料,对气溶胶的吸光特性进行了分析。首先根据黑碳气溶胶(BC)和棕色碳气溶胶(BrC)的光学特性差异对二者进行区分,然后分析两者的吸光特性。结果表明:观测期间亚微米气溶胶中黑碳和有机物的平均浓度分别为3.7μg·m~(-3)和29.3μg·m~(-3)。随着亚微米气溶胶浓度的增加,黑碳和棕色碳吸收系数均增加,但棕色碳吸收系数增加得更快。黑碳和棕色碳在550 nm处的平均吸收系数分别为(9.9±5.9)Mm~(-1)和(51.0±28.1)Mm~(-1)。棕色碳的Angstrom指数为4.4。另外,采用正定矩阵因子解析模型(PMF)将棕色碳的来源划分为六种(碳氢类有机气溶胶(HOA)、烹饪类有机气溶胶(COA)、生物质燃烧(BBOA)、燃煤排放(CCOA)、半挥发低氧化程度有机气溶胶(SV-OOA)和低挥发高氧化程度有机气溶胶(LV-OOA)),并通过多元线性回归方法计算了各来源的吸光贡献,其中BBOA和CCOA对棕色碳吸光系数的贡献为41.5%,其次是SVOOA(32.8%)、LV-OOA(14.2%)、HOA(7.8%)和COA(3.8%),说明一次和二次有机气溶胶均为兰州地区棕色碳的重要来源。
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| 关 键 词： | 兰州 黑碳 棕色碳 吸收系数 来源 |
Study on the absorption characteristics of winter aerosol in Lanzhou:the distinction between black carbon and brown carbon and a characteristic analysis |
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| Abstract: | The optical absorption properties and composition of non-refractory submicron aerosol were measured by the combination of aethalomerter and HR-ToF-AMS in Lanzhou, China, from 10th January through 4th Feb-ruary 2014. Black carbon and brown carbon from combustion were segregated by optical method. The average mass concentrations of black carbon and organics in PM1 were 3. 7 μg·m-3 and 29. 3 μg·m-3 , respectively. Visibility decreased exponentially with the increase of BC concentration. BrC absorption coefficient increased fas-ter than those of BC when haze became heavier. During the campaign, the absorption coefficient at 550 nm was (51. 0 ± 28. 1) Mm-1 for BC and (9. 9 ± 5. 9) Mm-1 for BrC, respectively. The absorption Angstrom exponent of BrC was approximately 4 . 4 . Source apportionment of organic aerosol detected by HR-TOF-AMS was per-formed by positive matrix factorization ( PMF) and six species of OA were identified, including hydrocarbon-like OA ( HOA ) , cooking-emission related OA ( COA ) , biomass burning OA ( BBOA ) , coal combustion OA ( CCOA) , semi-volatile oxygenated OA ( SV-OOA) and low-volatility oxygenated OA ( LV-OOA) . A multiple linear regression was used to calculate the relative absorption contribution of each species in OA. Thereinto, BBOA and CCOA accounted for 41. 5％ of the total absorption of BrC, followed by SV-OOA (32. 8％), LV-OOA (14. 2％), HOA(7. 8％) and COA (3. 8％), suggesting that POA and SOA might have contributed com-parably to BrC absorption coefficient in Lanzhou. |
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| Keywords: | Lanzhou black carbon brown carbon absorption coefficient sources |
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