Japan Geoscience Union Meeting 2018

Presentation information

[JJ] Oral

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

[A-CC29] Ice cores and paleoenvironmental modeling

Tue. May 22, 2018 9:00 AM - 10:30 AM 201A (2F International Conference Hall, Makuhari Messe)

convener:Ryu Uemura(University of the Ryukyus), Kenji Kawamura(National Institute of Polar Research, Research Organization of Information and Systems), Ayako Abe-Ouchi(東京大学大気海洋研究所, 共同), Nozomu Takeuchi(Chiba University), Chairperson:Takeuchi Nozomu(千葉大学), Hattori Shohei(東工大)

9:15 AM - 9:30 AM

[ACC29-02] Overview and recent activities for shallow ice core project on a high-accumulation dome, southeast Greenland

★Invited Papers

*Iizuka Yoshinori1, Sumito Matoba1, Ryoto Furukawa1, Takuto Ando1, Takeshi Saito1, Fahmida Parvin1, Tomomi Amino1, Mai Shibata1, Moe Kadota1, Osamu Seki1, Shin Sugiyama1, Ryu Uemura2, Koji Fujita3, Asuka Tsuruta4, Shohei Hattori4, Shuji Fujita5, Hideaki Motoyama5, Naoko Nagatsuka5, Ikumi Oyabu5, Satoru Yamaguchi6, Satoshi Adachi6, Hiroshi Ohno7, Akira Hori7, Chihiro Miyamoto8, Yoshio Takahashi8, Chiaki Sasaki9, Toshitaka Suzuki9, Angel T. Bautista VII10,11, Hiroyuki Matsuzaki10, Kazuho Horiuchi12, Atsushi Miyamoto13, Kei Yoshimura14, Jesper Sjolte15, Masashi Niwano16, Naga Oshima16, Akihiro Hashimoto16, Tetsuhide Yamasaki17, Teruo Aoki18 (1.Institite of Low Temperature Science, Hokkaido University, 2.Department of Chemistry, Biology, and Marine Science, Faculty of Science, University of the Ryukyus, 3.Graduate School of Environmental Studies, Nagoya University, 4.Department of Chemical Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology, 5.National Institute of Polar Research, 6.The National Research Institute for Earth Science and Disaster Prevention, 7.Department of Civil and Environmental Engineering, Kitami Institute of Technology, Hokkaido, Japan, 8.Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, 9.Faculty of Science, Yamagata University, 10.Department of Nuclear Engineering and Management, The University of Tokyo, 11.Philippine Nuclear Research Institute - Department of Science and Technology (PNRI-DOST), 12.Graduate School of Science and Technology, Hirosaki University, 13.Institute for the Advancement of Higher Education, Hokkaido University, 14.Institute of Industrial Science, The University of Tokyo, 15.Department of Geology, Quaternary Science, Lund University, 16.Meteorological Research Institute, Japan Meteorological Agency, 17.Avangnaq, 18.Graduate School of Natural Science and Technology, Okayama University)

Keywords:ice core, Greenland, high accumulation

On May 2015, we drilled a 90.45 m ice core in a high accumulation area of the southeastern Greenland Ice Sheet. The drilling site (SE-Dome; 67.18°N, 36.37°W, 3170 m a.s.l.) is located 185 km north of the town of Tasiilaq in southeastern Greenland [1]. Then we measure physical and chemical properties of the SE-Dome ice core. Based on the measurements, we show the general characteristics of the SE-Dome ice core. I) As for dating of the ice core [2], we propose a dating method based on matching the δ18O variations between ice-core records and records simulated by isotope-enabled climate models. We applied this method to a δ18O record from the SE-Dome ice core. The close similarity between the δ18O records from the ice core and models enables correlation and the production of a precise age scale, with an accuracy of a few months. II) As for physical property [3], the ice was –20.9 ºC at 20-m depth. The close-off density of 830 kg m-3 occurs at 83.4–86.8-m depth, which is about 20-m shallower than that obtained from empirical models, indicating that the firn with a higher density is softer than that from empirical result. We interpret that the high accumulation rate creates a high overburden pressure in a short time. The relative softness of the firn may arise from 1) there being not enough time to form bonds between grains as strong as those in a lower accumulation-rate area, and similarly, 2) the dislocation density in the firn being relatively high. III) As for chemical property [4], we measured the major ion fluxes, and obtained records of annual ion fluxes from 1957 to 2014. We find a high average NO3- flux (1.13 mmol m-2 yr-1) in the ice core, which suggests a negligible effect from post-depositional NO3- loss, indicating the SE-Dome region is an excellent location for reconstructing nitrate fluxes. For the non-sea-salt (nss) SO42- and NH4+ fluxes, a decreasing and increasing trend from 1970 to 2010, respectively, tracks well with the anthropogenic SOx and NH3 emissions. In contrast, the decadal trend of NO3- flux differs from the decreasing trend of anthropogenic NOx emissions. We continue to investigate the paleoenvironment with multi proxies from several analyses (e.g. [5]) of the high-time-resolution and chemicals-well-preserved ice core.

[1] Iizuka et al., (2016). Bulletin of Glaciological Research, 34, 1–10. https://doi.org/10.5331/bgr.15R03
[2] Furukawa et al., (2017). Journal of Geophysical Research: Atmospheres, 122, 10,873–10,887. https://doi.org/10.1002/2017JD026716
[3] Iizuka et al., (2017). Arctic, Antarctic, and Alpine Research, 49, 13–27. https://doi.org/10.1657/AAAR0016-034
[4] Iizuka et al., (2018). Journal of Geophysical Research: Atmospheres, 123. https://doi.org/10.1002/2017JD026733
[5] Bautista et al., (2018) Journal of Environmental Radioactivity 184–185, 14–21, https://doi.org/10.1016/j.jenvrad.2017.12.015