High-precision laser spectrometer for multiple greenhouse gas analysis in 1 mL air from ice core samples ...

• Main Authors: Bereiter, Bernhard, Tuzson, Béla, Scheidegger, Philipp, Kupferschmid, André, Looser, Herbert, Mächler, Lars, Baggenstos, Daniel, Schmitt, Jochen, Fischer, Hubertus, Emmenegger, Lukas
• Format: Text
• Language: English
• Published: Copernicus Publications 2020
• Subjects: 530 Physics; ice core
• Online Access: https://dx.doi.org/10.7892/boris.148603; https://boris.unibe.ch/148603/

The record of past greenhouse gas composition from ice cores is crucial for our understanding of global climate change. Future ice core projects will aim to extend both the temporal coverage (extending the timescale to 1.5 Myr) and the temporal resolution of existing records. This implies a strongly limited sample availability, increasing demands on analytical accuracy and precision, and the need to reuse air samples extracted from ice cores for multiple gas analyses. To meet these requirements, we designed and developed a new analytical system that combines direct absorption laser spectroscopy in the mid-infrared (mid-IR) with a quantitative sublimation extraction method. Here, we focus on a high-precision dual-laser spectrometer for the simultaneous measurement of CH4, N2O, and CO2 concentrations, as well as d13C(CO2). Flow-through experiments at 5 mbar gas pressure demonstrate an analytical precision (1 sigma) of 0.006 ppm for CO2, 0.02‰ for d13C(CO2), 0.4 ppb for CH4, and 0.1 ppb for N2O, obtained after ...