[A-CC29] Ice cores and paleoenvironmental modeling

[ACC29-08] Ice core analysis of southeastern dome, Greenland

★Invited Papers

*Iizuka Yoshinori¹, Kaoru Kawakami², Mahiro Sasage², Mai Matsumoto², Akira Hori³, Takeshi Saito¹, Keita Takasugi³, Takumi Hatakeyama⁴, AKIHISA WATARI², Nao Esashi⁵, Miu Otsuka², Atsushi Miyamoto⁶, Ryu Uemura⁵, Sakiko Ishino⁷, Shuji Fujita⁸, Teruo Aoki⁸, Koji Fujita⁵, Shohei Hattori⁹, Kazuho Horiuchi⁴, Motohiro Hirabayashi⁸, Kenji Kawamura⁸, Sumito Matoba¹ (1.Institite of Low Temperature Science, Hokkaido University, 2.Graduate School of Environmental Science, Hokkaido University, 3.Department of Earth and Environmental Engineering, Kitami Institute of Technology, 4.Graduate School of Science and Technology, Hirosaki University, 5.Graduate School of Environmental Studies, Nagoya University, 6.Hokkaido University, 7.Institute of Nature and Environmental Technology, Kanazawa University, 8.National Institute of Polar Research, 9.International Center for Isotope Effects Research, Nanjing University)

Keywords:ice core, Greenland, Anthropocene

The southeast dome of the Greenland ice sheet has one of the highest accumulation rates in Greenland (about 1.0 m water equivalent per year), depositing about four times as much snow as other Greenland domes and about 30 times as inland domes of Antarctica. The high accumulation rate has a disadvantage for ice core drilling, because it is not suitable for reconstructing the environment in older times. However, the high accumulation rate has an advantage of allowing environmental reconstructions with higher time resolution and is less post depositional effect of deposited aerosols. Therefore, the southeastern dome of the Greenland ice sheet is a suitable region for ice core drilling to precisely reconstruct the recent past, such as the Anthropocene (1850-present).

We drilled an ice core of about 250m in May 2021 under the projects of Grant-in-Aid for Scientific Research (project number 18H05292) and ArCS II (project number JPMXD1420318865). Subsequently, the ice core was imported to Japan at the end of November 2021, and we are engaged in the initial analysis of the ice core. The objectives of the initial analysis are to obtain a timescale and to elucidate physical properties of the ice core. For example, the hydrogen peroxide concentration is clearly defined events such as the Icelandic eruption in September 2014, the surface melting of Greenland in July 2012, and the Greenland coastal dust plume in August 2003. The deepest ice cores are estimated to be at least older than 1850, according to the Herron and Langway model based on the depth-density curve. From these measurements, we have established a monthly timescale for the ice core from 1850 to 2020, and are preparing more specialized analyses on a seasonal scale.