Climate effect of black carbon aerosol in a Tibetan Plateau glacier
Climate effect of black carbon aerosol in a Tibetan Plateau glacier
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DOI：
10.1016/j.atmosenv.2015.03.016
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发表时间：
2015-06
影响因子：
5
通讯作者：
Song Yang;Baiqing Xu;Junji Cao;C. Zender;Mo Wang
中科院分区：
文献类型：
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作者：
Song Yang;Baiqing Xu;Junji Cao;C. Zender;Mo Wang
在青藏高原，地表雪和雪坑中的黑碳（BC）浓度受到了较多关注，而雪中气溶胶浓度、垂直剖面、融化清除和富集的季节性行为受到的关注相对较少。在这里，我们研究了 2012 年融雪季节这些过程及其对青藏高原最西部木吉冰川辐射强迫的影响。杂质浓度的增加主要是由于沉积后效应而不是新沉积造成的。 7 月 5 日，地表雪中的 BC 浓度高于新雪，这意味着通过先前雪的升华和/或融化而富集。 7 月 27 日，新雪含有 25 ng g−1BC；此后，BC逐渐增加，9月份达到730.6 ng g−1。 BC、有机碳 (OC) 和粉尘浓度共同变化，但幅度不同。 OC 和 BC 的融雪清除效率估计分别为 0.19 ± 0.05 和 0.04 ± 0.01，并且地表雪中的 BC 根据融化强度增加了 20-25 倍。 BC 雪中辐射强迫 (RF) 对于新雪约为 2.2 W m−2，对于陈雪约为 18.1–20.4 W m−2，有时会因灰尘的存在而降低。
In the Tibetan Plateau, the black carbon (BC) concentration in surface snow and snow pits has received much attention, whereas the seasonal behavior of aerosol-in-snow concentration, vertical profile, melt-scavenging, and enrichment have received relatively little attention. Here we investigate these processes and their impacts on radiative forcing on the Muji glacier in the westernmost Tibetan Plateau during the 2012 snowmelt season. Increasing impurity concentrations were mostly due to post-deposition effects rather than new deposition. On 5 July, BC concentrations in the surface snow were higher than those of fresh snow, implying enrichment via sublimation and/or melting of previous snow. Fresh snow contained 25 ng g−1BC on 27 July; afterward, BC gradually increased, reaching 730.6 ng g−1in September. BC, organic carbon (OC), and dust concentrations co-varied but differed in magnitude. Melt-scavenging efficiencies were estimated at 0.19 ± 0.05 and 0.04 ± 0.01 for OC and BC, respectively, and the BC in surface snow increased by 20–25 times depending on melt intensity. BC-in-snow radiative forcing (RF) was approximately 2.2 W m−2for fresh snow and 18.1–20.4 W m−2for aged snow, and was sometimes reduced by the presence of dust.