Generating Ultra-High Resolution Paleoclimate Records from Ice Cores
About My Research
The introduction of Picarro analyzers, specifically water isotope instruments, has essentially revolutionized the Stable Isotope Lab at INSTAAR- University of Colorado, eventually replacing several mass spectrometers dedicated to water isotopes. With the Picarro instruments, we are able to measure many more samples, faster, cheaper and better. In addition, the laser-based spectroscopy has opened many doors to avenues of research that were previously not possible. For example, the ability to measure both d18O and dD at the same time on the same sample has allowed us to create robust deuterium excess records from discrete samples of ice cores. But coupling the Picarro with continuous flow analysis (CFA) ice core melter-systems, has catapulted us from producing paleo climate records consisting of ~20 samples per meter of ice with traditional discrete sample methods, to making over 2,000 analyses per meter with the CFA system. This explosion of data has generated ultra-high resolution paleoclimate records from ice cores, allowing ever more detailed look a phasing and timing of climate events in the paleo record from ice cores. Some of these results are published in at least two Nature papers based on this method. {REFS: Nature, 554(7692), 351-355, doi.org/10.1038/nature24669;Jones, T.R., Cuffey, K.M., Roberts, W.H.G. et al. Seasonal temperatures in West Antarctica during the Holocene. Nature 613, 292–297 (2023). https://doi.org/10.1038/s41586-022-05411-8;Jones, Tyler R. and Cuffey, Kurt M., Roberts, William H. G. Markle, Bradley R., Steig, Eric J., Stevens, C. Max, Valdes, Paul J. , Fudge, T. J., Sigl, Michael, Hughes, Abigail G.., Morris, Valerie, Vaughn, Bruce H., Garland, Joshua, Vinther, Bo M. , Rozmiarek, Kevin S., Brashear, Chloe A., and White, James W. C. (2018). Southern Hemisphere climate variability forced by Northern Hemisphere ice-sheet topography.}
How Picarro Analyzers Helped
Ice cores are not the only area in which Picarro instruments have played a key role. We are also using Picarro instruments to measure the water vapor isotopes directly above the Greenland Ice Sheet, using uncrewed aircraft, helping to better understand the 2-way flux between the atmosphere and the ice sheet. There are implications for climate models as well as paleoclimate interpretations from ice cores. In another project, we are using a Picarro methane isotope instrument to fingerprint methane emissions from permafrost in Alaska. Samples are collected in glass flasks from either ground-based measurement pods, or airborne sample pods flown on uncrewed aircraft over potential sources of methane. In both cases we can measure flask samples for methane concentration and carbon isotopes, to help distinguish sources as biogenic or thermogenic in nature. Our hope is to help validate other measurement methods to better quantify emissions that can be scaled based on the landscape type for larger areas. Understanding methane emissions for high latitude areas is critical for gaining insight into the global methane budget. This complements our measurements on methane isotopes from the NOAA network of global sampling sites. Measurements across all scales will be key to understanding the future of atmospheric methane.