Articles | Volume 9, issue 4
https://doi.org/10.5194/amt-9-1939-2016
https://doi.org/10.5194/amt-9-1939-2016
Research article
 | 
29 Apr 2016
Research article |  | 29 Apr 2016

Influence of the melting temperature on the measurement of the mass concentration and size distribution of black carbon in snow

Takeshi Kinase, Kazuyuki Kita, Yoshimi Tsukagawa-Ogawa, Kumiko Goto-Azuma, and Hiroto Kawashima

Abstract. The influence of temperature and time of snow sample melting on the measurement of mass concentration and size distribution of black carbon (BC) in snow was evaluated experimentally. In the experiments, fresh (Shirouma) and aged (Hakusan) snow samples were melted at different temperatures or at different time lengths, and the BC mass concentration and size distribution in the melted snow samples were measured using a nebulizer and a single-particle soot photometer (SP2). In the experiment where melting temperature was varied, the BC mass concentration in the liquid decreased at a melting temperature of 70 °C. This decrease was 8.0 % for the Shirouma sample and 46.4 % for the Hakusan sample and depended on BC particle size, with a significant decrease found at BC diameters less than 350 nm. A similar decrease in BC mass concentration was found when the Hakusan snow sample that had been melted at 5 °C was heated to 70 °C. The experiment in which melting time was varied indicated that BC mass concentration in the liquid did not change for the Shirouma sample but decreased significantly with a longer melting time for the Hakusan sample (38.6 %). These results indicate that melting of snow samples at high temperatures or over long time periods can significantly affect the measurement of BC mass and its size distribution, especially for aged snow samples.

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Short summary
The influence of temperature and time for the melting snow samples on the measurement of mass concentration and its size distribution of black carbon (BC) in snow have not been understood enough. We evaluated the effect of the melting temperature and time with experiments. We also derived the best conditions of temperature and time for melting snow samples for the measurement of BC in snow by a single-particle soot photometer (SP2).