Japan Geoscience Union Meeting 2019

Presentation information

[J] Oral

A (Atmospheric and Hydrospheric Sciences ) » A-CC Cryospheric Sciences & Cold District Environment

[A-CC26] Ice cores and paleoenvironmental modeling

Tue. May 28, 2019 9:00 AM - 10:30 AM 201B (2F)

convener:Ryu Uemura(University of the Ryukyus), Kenji Kawamura(National Institute of Polar Research, Research Organization of Information and Systems), Ayako Abe-Ouchi(Atmosphere and Ocean Research Institute, The University of Tokyo), Nozomu Takeuchi(Chiba University), Chairperson:Ryu Uemura(University of the Ryukyus), Ikumi Oyabu(National Institute of Polar Research)

9:45 AM - 10:00 AM

[ACC26-04] Temporal variations of concentrations, size distributions, and seasonal variations of anthropogenic and natural black carbon in Greenland

*Kumiko Goto-Azuma1,2, Yoshimi Ogawa-Tsukagawa1, Yutaka Kondo1, Remi Dallmayr1,10, Motohiro Hirabayashi1, Jun Ogata1, Kyotaro Kitamura1, Kenji Kawamura1,2, Hideaki Motoyama1,2, Sumito Matoba3, Teruo Aoki4, Nobuhiro Moteki5, Sho Ohata5, Tatsuhiro Mori6, Makoto Koike5, Yuki Komuro7, Akane Tsushima8,9, Naoko Nagatsuka1, Wataru Shigeyama1,2, Koji Fujita9 (1.National Institute of Polar Research, 2.SOKENDAI, 3.Hokkaido University, 4.Okayama University, 5.University of Tokyo, 6.University of Science, 7.Yamagata University, 8.Research Institute for Humanity and Nature, 9.Nagoya University, 10.AWI)

Keywords:Black carbon, Greenland, Ice core

An ice core retrieved at the SIGMA-D site, Northwest Greenland, in 2014 was analyzed down to the depth of 113 m. Between 6 and 113 m depths, we used a Continuous Flow Analysis (CFA) system developed at the National Institute of Polar Research. The CFA system enabled us to obtain high resolution data of black carbon (BC), stable isotopes of water, microparticles and six elements (Na, K, Mg, Ca, Fe, and Al). The top 6 m of the core was cut at a ca 5 cm interval, melted and analyzed. For BC analysis, we used a recently developed Wide-range SP2 (Single Particle Soot Photometer). We dated the core by annual layer counting using mainly Na and water stable isotopes, with occasional use of other impurities. We divided a year into 12 months and calculated monthly averaged BC concentrations and size distributions.
Here we report the variability of monthly resolved BC concentrations and size distributions over the past 350 years. BC number and mass concentrations started to increase in the 1870s, reached its maximum in the 1920s - 1930s, and decreased again since then. The increases are likely due to anthropogenic input. The increases are most significant in fall and winter months. We find anthropogenic changes in seasonality of BC concentration: annual concentration peak shifted from summer to winter. We also find anthropogenic changes in size distribution of BC: the mode diameter of mass concentration and average mass of BC particles became larger. This suggests that anthropogenic BC particles are larger than natural ones in the snow deposited in Greenland. Apart from anthropogenic BC, BC concentration occasionally showed large spikes in summer. They are likely originated from biomass burnings. We will compare the results from the SIGMA-D core with those from other ice cores drilled in Greenland and discuss spatial variations of BC.