Radiative Absorption Enhancements Due to the Mixing State of Atmospheric Black Carbon
Radiative Absorption Enhancements Due to the Mixing State of Atmospheric Black Carbon
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DOI：
10.1126/science.1223447
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发表时间：
2012-08-31
期刊：
影响因子：
56.9
通讯作者：
Zaveri, Rahul A.
中科院分区：
文献类型：
--
作者：
Cappa, Christopher D.;Onasch, Timothy B.;Zaveri, Rahul A.
大气黑碳（BC）使地球气候变暖，其减少已成为近期减缓气候变化的目标。包括BC强迫的模型假设与非BC气溶胶成分的内部混合，增强BC吸收，通常以类似于2的因子;这种模型估计尚未通过大气观测明确验证。在这里，直接在现场测量的BC吸收增强（E-abs）和混合状态的报告为两个加州地区。所观察到的E-abs是小的-在532 nm处平均为6%-并且随着光化学老化而微弱地增加。E-abs小于观测约束理论计算的预测，表明许多气候模型可能高估了BC的变暖。这些环境观测结果与实验室测量结果形成鲜明对比，实验室测量结果表明，BC的大量E-abs是可能的。
Atmospheric black carbon (BC) warms Earth's climate, and its reduction has been targeted for near-term climate change mitigation. Models that include forcing by BC assume internal mixing with non-BC aerosol components that enhance BC absorption, often by a factor of similar to 2; such model estimates have yet to be clearly validated through atmospheric observations. Here, direct in situ measurements of BC absorption enhancements (E-abs) and mixing state are reported for two California regions. The observed E-abs is small-6% on average at 532 nm-and increases weakly with photochemical aging. The E-abs is less than predicted from observationally constrained theoretical calculations, suggesting that many climate models may overestimate warming by BC. These ambient observations stand in contrast to laboratory measurements that show substantial E-abs for BC are possible.