@article{9614632ed7cb448ab012b57983e08a80,
title = "Temperature-Driven Bubble Migration as Proxy for Internal Bubble Pressures and Bubble Trapping Function in Ice Cores",
abstract = "Ice core data record significant and abrupt past climate changes that are associated with large and rapid changes in atmospheric greenhouse gases, such as methane. Due to the gradual close-off of gas bubbles and the relatively fast diffusion of gases within the firn column, even a discrete or quick step increase in air composition may be smoothed or integrated in the data; current laboratory analyses of gases consider the mean gas content value across all bubbles in a sample, rather than the content of individual bubbles. The convolution of the distribution of trapping ages with the history of atmospheric composition thus smears the measured gas record in each sample. We developed a nondestructive method to determine pressure distribution in all bubbles in a sample and estimate the shape of the trapping function derived from that bubble pressure distribution and site characteristics. Our method works not only for present conditions but also through varying paleo-atmospheric conditions, while providing accurate measurements of morphological bubble properties. The method is based on using temperature-driven air bubble migration as a proxy for the pressure of individual bubbles, which we combine with a model for bubbly ice densification to obtain the gas trapping functions and constrain the age distribution of air bubbles for past conditions, which are preserved at different depths. The trapping functions will help us to obtain a more accurate gas signal in the future that is less attenuated through the age distribution of the gas during the close-off process.",
author = "R. Dadic and M. Schneebeli and M. Wiese and Bertler, {N. A.N.} and Salamatin, {A. N.} and Theile, {T. C.} and Alley, {R. B.} and Lipenkov, {V. Ya}",
note = "Funding Information: This work was funded by the New Zealand Royal Society Marsden Fund (VUW1314 and 15‐VUW‐131), by the New Zealand Ministry of Business, Innovation, and Employment Grants through Victoria University of Wellington (RDF‐VUW‐1103) and GNS Science (540GCT32 and 540GCT12), and Antarctica New Zealand (K049). M. Wiese was funded by the Swiss National Science Foundation (200021‐143839).We would like to thank the WSL Institute for Snow and Avalanche Research SLF for hosting R. Dadic and making the laboratory work possible. M. Jaggi coordinated the ice core sample transport and storage and provided help in the laboratory at SLF. GNS Science and R. Pyne provided cold laboratory space and support for the second set of experiments with the microscope. A. Staffensdottir set up and conducted those experiments with the help of A. Pyne, A. Benson, D. Mandeno, and R. Pyne. A. Beliaev always found a solution for computer‐related difficulties, and B. Anderson and H. Horgan gave valuable feedback on ice processes. M. Winstrup, H. Conway, J.Lee, and E. Brook shared invaluable data from the RICE core. This work is a contribution to the Roosevelt Island Climate Evolution (RICE) Program, funded by national contributions from New Zealand, Australia, Denmark, Germany, Italy, the People's Republic of China, Sweden, the United Kingdom, and the United States. The main logistics support was provided by Antarctica New Zealand (K049) and the US Antarctic Program. We are grateful to the editor and the reviewers for their constructive comments, which improved the manuscript significantly. The data from our experiments are available at https://doi.org/10.1594/PANGAEA.905074 . Funding Information: This work was funded by the New Zealand Royal Society Marsden Fund (VUW1314 and 15-VUW-131), by the New Zealand Ministry of Business, Innovation, and Employment Grants through Victoria University of Wellington (RDF-VUW-1103) and GNS Science (540GCT32 and 540GCT12), and Antarctica New Zealand (K049). M. Wiese was funded by the Swiss National Science Foundation (200021-143839).We would like to thank the WSL Institute for Snow and Avalanche Research SLF for hosting R. Dadic and making the laboratory work possible. M. Jaggi coordinated the ice core sample transport and storage and provided help in the laboratory at SLF. GNS Science and R. Pyne provided cold laboratory space and support for the second set of experiments with the microscope. A. Staffensdottir set up and conducted those experiments with the help of A. Pyne, A. Benson, D. Mandeno, and R. Pyne. A. Beliaev always found a solution for computer-related difficulties, and B. Anderson and H. Horgan gave valuable feedback on ice processes. M. Winstrup, H. Conway, J.Lee, and E. Brook shared invaluable data from the RICE core. This work is a contribution to the Roosevelt Island Climate Evolution (RICE) Program, funded by national contributions from New Zealand, Australia, Denmark, Germany, Italy, the People's Republic of China, Sweden, the United Kingdom, and the United States. The main logistics support was provided by Antarctica New Zealand (K049) and the US Antarctic Program. We are grateful to the editor and the reviewers for their constructive comments, which improved the manuscript significantly. The data from our experiments are available at https://doi.org/10.1594/PANGAEA.905074. Publisher Copyright: {\textcopyright}2019. American Geophysical Union. All Rights Reserved.",
year = "2019",
month = sep,
day = "1",
doi = "10.1029/2019JD030891",
language = "English (US)",
volume = "124",
pages = "10264--10282",
journal = "Journal of Geophysical Research: Atmospheres",
issn = "2169-897X",
number = "17-18",
}
