Earth System Research Laboratory Carbon Cycle and Greenhouse Gases Group Flask-Air Sample Measurements of CH4 at Global and Regional Background Sites, 1967-Present

The CCGG cooperative air sampling network effort began in 1967 at Niwot Ridge, Colorado. Today, the network is an international effort which includes regular discrete samples from the NOAA ESRL/GML baseline observatories, cooperative fixed sites, and commercial ships. Air samples are collected approximately weekly from a globally distributed network of sites. Samples are analyzed for Carbon Dioxide (CO2), Methane (CH4), Carbon Monoxide (CO), Hydrogen Gas (H2), Nitrous Oxide (N2O), and Sulfur Hexafluoride (SF6); and by INSTAAR for the stable isotopes of CO2 and CH4 and for many volatile organic compounds (VOC) such as ethane (C2H6), ethylene (C2H4) and propane (C3H8). Measurement data are used to identify long-term trends, seasonal variability, and spatial distribution of carbon cycle gases.