Digital Imaging of Ice Cores: Early Results

Ice core science addresses fundamental questions of human interest related to global warming, abrupt climate change, biogeochemical cycling and more, and directly informs policymakers. The National Ice Core Laboratory (NICL) in Denver, Colorado, is currently developing a high-resolution optical scanning system for laboratory curation in order to expand the accessibility of ice core data sets through creation of a digital archive of ice core images. Additional goals of this project include development of internet-based search and retrieval capabilities from this digital archive; development of a digital image analysis system specifically for ice core studies; integration of digital optical data with other dating methods and testing of the image processing tools in scientific investigations. By providing permanent online digital archives of core quality, it will allow improved selection of samples, and documentation of possible core-quality artifacts for all U.S. ice core scientists. This project will allow any researcher to examine the core in similar detail to the few investigators who were fortunate enough to observe it before modifications from sampling and storage. This re-examination can be done decades later by anyone at any location, which is not possible now because only the interpretation of the original observer is recorded. Integration of this digital optical examination into ice core analysis will speed discovery, allow collaborative interpretation, and enhance consistency of analysis to improve ice core dating, identification of melt layers, location of flow disturbances, and more. Here we report on the current status of, and latest results from, these development efforts, including examples of images from the GISP2 (Greenland Ice Sheet Project Two) ice core. Preliminary work on this core shows that the imaging system successfully and accurately captures numerous features readily recognized by (trained) human observers, such as layering from changes in dust content and seasonal variability, dips and folds (including boudins), and melt layers.