[M-IS08] Global climate change driven by the Southern Ocean and the Antarctic Ice Sheet

[MIS08-01] Temporal variations of surface mass balance over the last 5000 years around Dome Fuji, Dronning Maud Land, East Antarctica

★Invited Papers

*Ikumi Oyabu¹, Kenji Kawamura^1,2,3, Shuji Fujita^1,2, Ryo Inoue², Hideaki Motoyama^1,2, Kotaro Fukui⁴, Motohiro Hirabayashi¹, Hoshina Yu⁵, Naoyuki Kurita⁵, Fumio Nakazawa^1,2, Hiroshi Ohno⁶, Konosuke Sugiura⁷, Toshitaka Suzuki⁸, Shun Tsutaki^1,2, Ayako Abe-Ouchi⁹, Masashi Niwano¹⁰, Frédéric Parrenin¹¹, Fuyuki SAITO³, Masakazu Yoshimori⁹ (1.National Institute of Polar Research, Research Organization of Information and Systems, 2.The Graduate University for Advanced Studies, SOKENDAI, 3.Japan Agency for Marine Science and Technology, 4.Tateyama Caldera Sabo Museum, 5.Nagoya University, 6.Kitami Institute of Technology, 7.University of Toyama, 8.Yamagata University, 9.Atmosphere and Ocean Research Institute, The University of Tokyo, 10.Meteorological Research Institute, Japan Meteorological Agency, 11.Institut des Géosciences de l'Environnement, Université Grenoble Alpes)

Keywords:Accumulation rate, Surface mass balance, Antarctica, Ice sheet, Ice core, Holocene

We reconstructed surface mass balance (SMB) around Dome Fuji, Antarctica, over the last 5000 years using the data from 15 shallow ice cores and 7 snow pits. The depth-age relationships for the ice cores were determined by synchronizing them with a layer-counted ice core from West Antarctica (WAIS Divide ice core) using volcanic signals. The reconstructed SMB records for the last 4000 years show spatial patterns that may be affected by their locations relative to the ice divides around Dome Fuji, proximity to the ocean, and wind direction. The SMB records from the individual ice cores and snow pits were stacked to reconstruct the SMB history in the Dome Fuji area. The stacked record exhibits a long-term decreasing trend at -0.037±0.005 kg m^-2 per century over the last 5000 years in the preindustrial period. The decreasing trend may be the result of long-term surface cooling over East Antarctica and the Southern Ocean, and sea-ice expansion in the water vapor source areas. The multidecadal to centennial variations of the Dome Fuji SMB after detrending the record shows four distinct periods during the last millennium: mostly negative period before 1300 C.E., slightly positive for 1300–1450 C.E., slightly negative for 1450–1850 C.E. with a weak maximum around 1600 C.E., and strong increase after 1850 C.E. These variations are consistent with those of previously reconstructed SMB records in the East Antarctic plateau. The low accumulation rate periods tend to coincide with the combination of strong volcanic forcings and solar minima for the last 1000 years, but the correspondence is not clear for the older periods, possibly because of the lack of coincidence of volcanic and solar forcings, or the deterioration of the SMB record due to smaller number of stacked cores.