Variations of Concentrations and Sizes of Black Carbon Particles in Northwest Greenland over the Past 350 years

An ice core to the depth of 225 m was drilled at the SIGMA-D site, Northwest Greenland, in 2014 under the SIGMA (Snow Impurity and Glacial Microbe Effects on Abrupt Warming in the Arctic) project (Matoba et al., 2015). We analyzed the ice core to the depth of 113 m using a Continuous Flow Analysis (CFA) system at the National Institute of Polar Research (NIPR), Japan. The NIPR CFA system allowed high resolution analyses of black carbon (BC), stable isotopes of water, microparticles, electric conductivity, and six elements (Na, K, Mg, Ca, Fe, and Al). We used a Wide-range SP2 (Single Particle Soot Photometer, Droplet Measurement Technologies) for BC analysis. While an SP2 detects BC particles in the size range between 70 and 800 nm, the Wide Range SP2 enabled us to detect BC particles in the size range between 70 and 4000 nm (Mori et al., 2016).

We dated the ice core by annual layer counting using stable water isotope ratios and Na concentrations. We then divided each year into 12 months. Here we present monthly resolved BC concentrations and sizes over the past 350 years. BC concentrations started to increase in the 1890s, reached its maximum in the 1930's - 1940's, and decreased again since then. The increase is likely due to fossil fuel combustion. Apart from this general temporal trend, we occasionally find high concentration peaks lasting only for short periods. These peaks are likely due to biomass burning. When BC concentrations increased due to inflow of fossil fuel combustion and biomass burning aerosols, BC sizes also increased.

References

Matoba, S., H. Motoyama, K. Fujita. T. Yamasaki, M. Minowa, Y. Onuma Y. Komuro, T. Aoki, S. Yamaguchi, S. Sugiyama and H. Enomoto, Glaciological and meteorological observations at the SIGMA-D site, northwestern Greenland Ice Sheet. Bulletin of Glaciological Research, 33, 7-10, 2015.

Mori, T., N. Moteki, S. Ohata, M. Koike, K. Goto-Azuma, Y. Miyazaki and Y. Kondo, Improved technique for measuring the size distribution of black carbon particles in liquid water, Aerosol Science & Technology, 50, 3, 242-254, DOI: 10.1080/02786826.2016.1147644, 2016.