High loadings of anthropogenic carbonaceous aerosols in Chinese air influencethe air quality for over one billion people and impact the regional climate.A large fraction (17–80%) of this aerosol carbon is water-soluble,promoting cloud formation and thus climate cooling. Recent findings, however,suggest that water-soluble carbonaceous aerosols also absorb sunlight,bringing additional direct and indirect climate warming effects, yet theextent and nature of light absorption by this water-soluble "brown carbon"and its relation to sources is poorly understood. Here, we combine sourceestimates constrained by dual carbon isotopes with light-absorptionmeasurements of water-soluble organic carbon (WSOC) for a March 2011 campaignat the Korea Climate Observatory at Gosan (KCOG), a receptor station in SEYellow Sea for the outflow from northern China. The mass absorption crosssection at 365 nm (MAC365) of WSOC for air masses from N. China were ingeneral higher (0.8–1.1 m2 g?1), than from other source regions(0.3–0.8 m2 g?1). However, this effect corresponds to only2–10% of the radiative forcing caused by light absorption by elementalcarbon. Radiocarbon constraints show that the WSOC in Chinese outflow hadsignificantly higher fraction fossil sources (30–50%) compared toprevious findings in S. Asia, N. America and Europe. Stable carbon(δ13C) measurements were consistent with aging during long-rangeair mass transport for this large fraction of carbonaceous aerosols.
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机译：中国空气中高含量的人为碳质气溶胶影响着超过十亿人口的空气质量，并影响区域气候。这种气溶胶碳的很大一部分（17-80％）是水溶性的，从而促进了云的形成，从而促进了气候的降温。然而，最近的发现表明，水溶性碳质气溶胶也吸收阳光，带来了额外的直接和间接的气候变暖效应，但是人们对这种水溶性“棕碳”的光吸收范围和性质及其与光源的关系知之甚少。在这里，我们将受双重碳同位素约束的源估计与水溶性有机碳（WSOC）的光吸收测量相结合，以进行2011年3月在韩国黄山气候观测站（KCOG）的活动，该站是SEYellow Sea接收站从中国北方流出的。来自中国北方地区的空气质量团在WSOC的365 nm处的质量吸收截面（MAC 365 ）通常更高（0.8–1.1 m 2 g ？1 < / sup>），而不是其他来源区域（0.3-0.8 m 2 g ？1 ）。但是，这种效应仅相当于元素碳吸收光引起的辐射强迫的2-10％。放射性碳的限制表明，与先前在南美，北美和欧洲的发现相比，中国流出的WSOC的化石来源比例高得多（30％至50％）。对于这大部分碳质气溶胶，稳定的碳（δ 13 C）测量值与远程空气质量传输期间的老化相一致。
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