Towards an understanding of the controls on δO2/N2 variability in ice core records

• Main Authors: Harris Stuart, Romilly, Landais, Amaëlle, Arnaud, Laurent, Buizert, Christo, Capron, Emilie, Dumont, Marie, Libois, Quentin, Mulvaney, Robert, Orsi, Anaïs, Picard, Ghislain, Prié, Frédéric, Severinghaus, Jeffery, Stenni, Barbara, Martinerie, Patricia
• Format: Text
• Language: English
• Published: 2024
• Subjects: ice core
• Online Access: https://doi.org/10.5194/egusphere-2023-2585; https://egusphere.copernicus.org/preprints/2023/egusphere-2023-2585/

While the processes controlling pore closure are broadly understood, the physical mechanisms driving the associated elemental fractionation remains ambiguous. Previous studies have shown that the pore closure process leads to a depletion in small-sized molecules (e.g. H 2 , O 2 , Ar, Ne, He) in ice core bubbles relative to larger-sized molecules like N 2 . This size-dependent fractionation, identified using ice core δ ( O 2 / N 2 ) <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="49pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="e4d76ebc952016283d37007278f6b1ba"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="tc-18-3741-2024-ie00004.svg" width="49pt" height="14pt" src="tc-18-3741-2024-ie00004.png"/> </svg:svg> records, exhibits a clear anti-correlation with local summer solstice insolation, making δ ( O 2 / N 2 ) <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="49pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="23dc7679cf0e1a0a665444524913a3e3"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="tc-18-3741-2024-ie00005.svg" width="49pt" height="14pt" src="tc-18-3741-2024-ie00005.png"/> </svg:svg> a valuable ice core dating tool. Mechanisms controlling this relationship are attributed to the physical properties of deep firn. In this study, we compile δ ( O 2 / N 2 ) <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="49pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="96157c289844eb9f7df001c7882352a7"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="tc-18-3741-2024-ie00006.svg" width="49pt" height="14pt" src="tc-18-3741-2024-ie00006.png"/> </svg:svg> records from 15 polar ice cores and show a new additional link between δ ( O 2 / N 2 ) <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="49pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="28609d3e6f976a7c5045bed2b5599ee5"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" ...