日期: April 18, 2014
"Celebration: We Reached the Surface!"
It's time for a celebration at the Institute of Arctic and Alpine Research (INSTAAR) Stable Isotope Lab (SIL). Valerie Morris, Bruce Vaughn and the SIL team have reached the top of the WAIS Divide Ice Core! Using a custom-built continuous flow melt system coupled to a Picarro L2130-i, the SIL team has completed stable isotope analysis of the West Antarctic Ice Sheet Divide 06 A core. This is the first top-to-bottom continuous ultra-high resolution isotopic record from a polar ice core.
Bruce kindly shared some "wow" numbers with us:
- 3,404.07m of ice analyzed
- 8,174,400 individual δ18O and δD data points
- 403 days of melting and analyzing ice
- 12 technicians and students who sat for endless hours in front of the melter
- Countless 2 mL glass vials filled as back-ups... just in case!
The SIL team's achievement is especially significant because of the ultra-high resolution nature of the measurement. Compared to conventional ice core methodologies, which can yield approximately 24 to 50 samples for isotopic analysis per meter of ice, the continuous melter-Picarro combination yields more than 2,400 isotopic measurements per meter! This method builds upon the innovation that began with the Ice and Climate group in Copenhagen (Gkinis et al., 2011) and has brought it to a new level of reliability and production. This project is part of a NSF funded project "Ice in the Transition and Glacial Sections of the WAIS Divide Deep Ice Core", lead by Eric Steig & Jim White.
Using a Picarro L2130-i, the team made simultaneous δ18O and δD measurements of the water vapor evolved during the melting process. Stable isotopes of water are a proxy for the temperature of ice core deposition and give incredible insight into past global climate. Following relationships established by the stable isotope and Earth science community over the past 50 years, periods of high δ18O and δD, represent relatively warm, interglacial conditions. In contrast, periods of low δ18O and δD represent relatively cool periods, such as the Last Glacial Maximum about 20,000 years ago. With the continuous melter coupled to Picarro L2130-i it is now possible to see not only long-term variability in climate but also resolve warm summers from cold winters.
We are excited to have been a part of INSTAAR's research and congratulate them on this phenomenal achievement!
- INSTAAR WAIS Divide ice coring project
- West Antarctic Ice Sheet Divide Ice Core
- Picarro L2130-i
- Gkinis et al. (2011) "Water isotopic ratios from a continuously melted ice core sample"
(Photos courtesy of INSTAAR)