C: atm. methane
Photo Tour
Overview
In collaboration with the NOAA Carbon Cycle Group at the Climate Monitoring and Diagnostics Laboratory in Boulder, we analyze weekly samples from a subset of the global network of over 50 sites for isotopes of carbon atmospheric CH4. Currently we analyze for Methane at 11 sites from the larger network. Quantitative results from this long term atmospheric program play a key role in driving Global Climate Models (GCM's) and furthering our understanding of the role of greenhouse gases in climate change.
Flasks
2 1/2-Liter glass flasks are analyzed for mole fraction of CO2, CO, CH4, and H2 at the NOAA Carbon Cycle group in Boulder. They are physically transported to the Stable Isotope Lab at INSTAAR where they are analyzed for Carbon and Oxygen isotopes in atmospheric CO2.
Methane Separation
Atmospheric air samples are drawn into a 40cc sample isolation loop, preconcentrated with liquid nitrogen, and cyro-focused before being flushed through a column by helium where methane is separated from the co2 at 80°C, then combusted and dried before entering the mass spec.
Measurement
Finally they are analyzed for carbon isotopes in atmospheric methane using a Micromass brand, Isoprime, with a custom prep system with a 16 port manifold. Up to 40 cc of air sample are used. Typical reproducibility between multiple standards in one set of samples is ±0.04 d13C.