An improved method for filtering the measured stable oxygen isotope ratios from carbon dioxide of the NOAA/CMDL Network

• Other Authors: Zauscher, Melanie (author), White, James (contributor), Barnes, Timothy (contributor), Lefer, Barry (contributor)
• Format: Manuscript
• Language: English
• Published: 2004
• Subjects: carbon sinks; Arctic; Climate change; Institute of Arctic and Alpine Research
• Online Access: http://nldr.library.ucar.edu/repository/collections/SOARS-000-000-000-087; https://doi.org/10.5065/x1pb-1728

Stable oxygen isotope ratios (δ¹⁸O) can be used to better quantify sources and sinks of carbon dioxide (CO₂), a major greenhouse gas. Furthermore, because δ¹⁸O serves as a link between water and carbon cycles, it can be used to understand how climate change will impact precipitation. The Institute of Arctic and Alpine Research (INSTAAR), in collaboration with the National Oceanic and Atmospheric Administration (NOAA) Climate Monitoring Diagnostics Lab (CMDL), has been analyzing atmospheric sample from the NOAA/CMDL network for δ¹⁸O since 1989. However, measuring δ¹⁸O from CO₂ is no straight forward. Because it is known that oxygen isotopically exchanges between CO₂ and liquid water, especially in humid sites, CMDL has recently started drying the air during collection. Since there be good data from sites that may have not dried their samples, and since we desire to make the best use of the 15 years of collected data, we wanted to find a selection method by which we can use historical data with confidence. Therefore, a quality control filtering routine was developed, which takes sample site location and collection method information, to identify the most reliable δ¹⁸O – CO₂ samples. The validated dataset can now be used to further our understanding of CO₂ and the relationships between water and carbon cycles.