Earth System Research Laboratory Halocarbons and Other Atmospheric Trace Gases Chromatograph for Atmospheric Trace Species (CATS) Measurements

The Halocarbons and other Atmospheric Trace Species (HATS) group aims to quantify the distributions and magnitudes of sources and sinks for atmospheric nitrous oxide and halogen containing compounds. They utilize numerous types of platforms, including ground-based stations, towers, ships, aircraft, and balloons to accomplish their mission. HATS also measures chlorofluorocarbons (CFCs) at its various measurement sites. CFCs are nontoxic, nonflammable chemicals that contains atoms of carbon, chlorine, and fluorine. They are classified as halocarbons which are compounds that contain carbon and halogen atoms. CFCs were used as solvents, refrigerants, and aerosol sprays. While inert in the lower atmosphere, CFCs decompose in the upper atmosphere (stratosphere) with some of the released chlorine becoming active in destroying ozone in the stratosphere. Over time this lead to the creation of the "Ozone Hole" over the Antarctic. Monitoring the amounts of CFCs and other trace gases is important to tracking the growth or recovery of the Ozone Hole.

The Chromatograph for Atmospheric Trace Species (CATS) instruments have been in operation at the NOAA baseline observatories (Barrow, AK, Mauna Loa, HI, American Samoa, and South Pole, Antarctica) since 1999. The CATS instrument measure nitrous oxide (N2O), sulfur hexafluoride (SF6), chlorofluorocarbons (CFC-12 (CCl2F2), CFC-11 (CCl3F), and CFC-113 (CCl2F-CClF2)), Halon-1211 (CBrClF2), methyl chloroform (CH3CCl3), and carbon tetrachloride (CCl4). The CATS gas chromatographs are custom built instruments that contain separation columns, flow controllers, an air selection valve, and an electron capture detector; all used for making measurements.

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