[A-CC21] Ice cores and past environmental changes

[ACC21-01] Studies on variations of climate and ice sheet under the international deep ice core project at the North East Greenland Ice Stream

*Kumiko Goto-Azuma^1,2, Kenji Kawamura^1,2, Shuji Fujita^1,2, Jun'ichi Okuno^1,2, Ayako Abe-Ouchi³, Ralf Greve⁴, Fuyuki SAITO⁵, Tomoyuki Homma⁶, Nobuhiko Azuma⁶, Hiroyuki Enomoto^1,2, Hideaki Motoyama^1,2, Dorthe Dahl-Jensen⁷ (1.National Institute of Polar Research, 2.SOKENDAI, 3.University of Tokyo, 4.Hokkaido University, 5.JAMSTEC, 6.Nagoka University of Technology, 7.University of Copenhagen)

Keywords:EGRIP, Greenland, Ice core

The Greenland Ice Sheet has recently been experiencing drastic changes, such as extended summer melting and increasing mass losses. There is an urgent need to understand the mechanisms of such changes because they are directly linked to global sea level rise. Greenland ice cores have so far provided valuable information on melt events and changes in the surface mass balance in the past. Moreover, the data obtained from multiple deep ice cores drilled during the last few decades, combined with modeling studies, have recently enabled us to reconstruct the past changes of Greenland Ice Sheet elevation. The previous ice cores were drilled at sites with minimal horizontal ice flow, as the main purpose of the past ice coring projects was to reconstruct the past climate and environment at the drill sites. Information on ice flow dynamics obtained from such ice cores has therefore been limited.
Understanding the mechanisms of basal sliding and ice deformation is a prerequisite for better projections of the future changes of the Greenland Ice Sheet and sea level rise. To understand the Greenland Ice Sheet dynamics, the East Greenland Ice Core Project (EGRIP) was proposed by the University of Copenhagen. Japan, Germany, Norway, U.S.A., France and Switzerland have been invited to participate in this international project. Under EGRIP, a deep ice core to the bed will be drilled at the onset of the North-East Greenland Ice Stream (NEGIS), where horizontal flow velocity is expected to be several tens of meters per year. As NEGIS is the largest ice stream in Greenland, the EGRIP ice core will certainly advance our knowledge on the dynamics and past changes of the Greenland Ice Sheet. The EGRIP core will also give us an ideal opportunity to reconstruct the climate and environment changes during the early Holocene, which was considered to be warmer than today and should be an excellent analogue to the future Greenland affected by global warming. The results from the EGRIP core will fill the gap of our knowledge due to the lack of high-resolution, detailed ice core records from the early Holocene.
Japan will participate in the EGRIP under the ArCS (Arctic Challenge for Sustainability) project, a recently funded national project. The first EGRIP steering committee meeting was held in Copenhagen in late October 2015. At the meeting, drilling and fieldwork plans were presented by the University of Copenhagen. Scientific plans were proposed by all the participant nations. At the JpGU meeting, we will present the scientific purposes and plans, together with the current status of the EGRIP and logistic plans.