Real-Time Monitor of Clumped CO2 Isotope in Ambient Air

Greenhouse gas (GHG) emissions are the primary drivers of global climate change and hence there is a crucial need to quantify their sources and sinks. A powerful technique to help constrain source and sink strengths in GHG exchange processes is the analysis of the relative proportions of isotopic variants of GHG's. In this proposal, we focus on the most important GHG: carbon dioxide. The standard isotopes of carbon dioxide (13C-CO2 and 18O-CO2) are already being measured on a global scale (for example by NOAA and INSTAAR within the Global Greenhouse Gas Reference Network). We propose to demonstrate and commercialize new isotopic measurement capabilities for more exotic isotopes of carbon dioxide that are difficult to measure with existing techniques. Specifically, we propose using Tunable Infrared Laser Direct Absorption Spectroscopy (TILDAS) to measure the primary clumped isotope of CO2 (Δ13C18O16O) and to simultaneously measure the mass independent 17O content (Δ17O). The proposed instrument will directly measure atmospheric samples with no need for chemical separation and will report isotopic ratios with 0.02 per mil repeatability and with time resolution of 2 to 3 minutes. The instrument will be sufficiently compact to be field or flight deployable thus providing the possibility of continuous high accuracy measurements of Δ13C18O16O and Δ17O rather than occasional flask samples.