An extended‐range Single Particle Soot Photometer (SP2) coupled to a Marin‐5 nebulizer was used to measure the refractory black carbon (rBC) mass and number size distributions in 1,004 samples from a West Antarctica snow/firn core. The SP2 was calibrated using Aquadag and a Centrifugal Particle Mass Analyzer for BC particles ranging from 0.5 to 800 fg. Our results indicate a significant contribution of rare, large particles of mass‐equivalent diameter (D_BC) > 500 nm to the total rBC mass (36%), while small particles (D_BC < 100 nm) are abundant but contribute <8% to total rBC mass. We observed a primary mass median diameter of 162 ± 40 nm, smaller than reported for snow in other regions of the globe but similar to East Antarctica rBC size distributions. In addition, we observed other modes at 673, 1,040, and >1,810 nm (uncontained mode). We compared two sets of samples from different seasons (wet vs. dry) and observed that dry season concentrations are 3.4 and 2 times that of the wet season in the ranges of 80 nm < D_BC < 500 nm (small particles) and 500 nm < D_BC < 2,000 nm (large particles), respectively, while number of particles in the dry season is 3.5 and 2 times that of the wet season for the same size ranges. Millimeter thick melt layers have been observed in some samples, although they did not change the observed median diameter. This study provides the first detailed rBC mass and number size distribution from West Antarctica.

中文翻译：

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南极西部松岛冰川雪和粉尘样品中rBC的质量和数量分布

与Marin-5雾化器耦合的扩展型单颗粒煤烟光度计（SP2）用于测量来自南极西部雪/粉芯的1,004个样品中的难熔黑碳（rBC）质量和数量大小分布。使用Aquadag和离心颗粒质量分析仪对SP2进行校准，以测量0.5至800 fg的BC颗粒。我们的结果表明，质量当量直径（D _BC）> 500 nm的稀有大颗粒对总rBC质量（36％）有显着贡献，而小颗粒（D _BC <100 nm）是丰富的，但对总rBC质量的贡献却小于8％。我们观察到的主要质量中值直径为162±40 nm，比全球其他地区的降雪要小，但与南极东部rBC大小分布相似。此外，我们在673、1,040和> 1,810 nm处观察到其他模式（非封闭模式）。我们比较了不同季节的两组样品（湿与干），发现在80 nm < D _BC  <500 nm（小颗粒）和500 nm范围内，干季浓度是湿季浓度的3.4倍和2倍。  <  d _BC 分别小于2,000 nm（大颗粒），而在相同尺寸范围内，干燥季节的颗粒数是潮湿季节的3.5倍和2倍。在某些样品中已观察到毫米厚的熔体层，尽管它们没有改变观察到的中值直径。这项研究提供了来自南极洲西部的第一个详细的rBC质量和数量大小分布。