Earth System Research Laboratory Halocarbons and Other Atmospheric Trace Gases Old Flask Gas Chromatograph (GC) Measurements

The Halocarbons and other Atmospheric Trace Species (HATS) group aims to quantify the atmospheric burden, and the distributions and magnitudes of sources and sinks for nitrous oxide and other halogen containing compounds. They utilize numerous types of platforms, including ground-based stations, towers, ships, aircraft, and balloons to accomplish their mission. HATS measures chlorofluorocarbons (CFCs) at measurement sites spanning the globe. CFCs are non-toxic, non-flammable chemicals that contain carbon, chlorine, and fluorine atoms. CFCs were used as solvents, refrigerants, and aerosol sprays. While inert in the troposphere, they decompose in the stratosphere to release chlorine for destructive reactions with ozone. This process eventually led to the creation of the "Ozone Hole" over the Antarctic. Monitoring the amounts of CFCs and other trace gases is important, both for tracking the growth and recovery of the Ozone Hole, and because many upward trending trace gases are potent and durable greenhouse gases.

Original flask sampling electron capture gas chromatograph ("Pre-Otto") : Air samples collected in flasks at five remote sites, including Barrow, AK (BRW), Mauna Loa, HI (MLO), American Samoa (SMO), South Pole (SPO), Antarctica, and Niwot Ridge, CO (NWR), were analyzed using the HATS group's original electron capture gas chromatograph (GC-ECD) system beginning in 1977. Two additional sites at Alert, Nunavut, Canada (ALT), and Cape Grim, Tasmania (CGO) were added prior to the original Pre-Otto system's retirement in 1995, when it was replaced by a newer, automated system called "Otto". This program was originally set up under the Geophysical Monitoring for Climatic Change (GMCC) division of NOAA's Air Resources Laboratory. Air was collected weekly at these sites in stainless-steel flasks and analyzed for nitrous oxide (N2O), and the chlorofluorocarbons CFC-11 (CCl3F) and CFC-12 (CCl2F2) in the Boulder labs in Colorado.

Through the Big Earth Data Initiative (BEDI), ESRL/GMD has taken their data collection and converted files into NetCDF-4, a self-describing format.