JpGU-AGU Joint Meeting 2017

Presentation information

[EJ] Poster

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

[A-CC37] [EJ] Ice cores and past environmental changes

Tue. May 23, 2017 5:15 PM - 6:30 PM Poster Hall (International Exhibition Hall HALL7)

[ACC37-P09] Variation trend of 17O-excess in an Arctic ice core

★Invited papers

*Akane Tsushima1, Vasileios Gkinis2, Kumiko Goto-Azuma3, Sumito Matoba4, Hideaki Motoyama3 (1.Research Institute for Humanity and Nature, 2.Niels Bohr Institute, University of Copenhagen, 3.National Institute of Polar Research, 4.Institute of Low Temperature Science, Hokkaido University)

Keywords:ice core, Arctic region, 17O-excess

Ice cores obtained from glaciers and ice sheets are important archives for reconstructing changes in the paleoclimate. The most important climate changes, such as the variation in temperature, precipitation, and the hydrological cycle, are reconstructed from stable water isotope ratios (δ18O, δD, and a second-order parameter, the d-excess, defined as d−excess = δD − 8δ18O) measured in ice cores.
With the improvment of water isotope analyzers, the ability to measure δ17O in water with high precision provided another second−order parameter, the 17O−excess, defined as 17O−excess = ln (δ17O+1) − 0.528 ∗ ln(δ18O+1). Previous studies reported that 17O−excess in polar snow is mainly controlled by the relative humidity in the water vapor source region, therefore expected as a new proxy of past climate change. However, at the present, there are few studies of 17O−excess in ice core, and therefore an undrestanding of variation factor of that is incomplete.
In this study, we analyzed δ17O and 17O−excess in an ice core which was drilled in Alaska. We also discussed the variation factors of those associated with environmental change.