Earth System Research Laboratory Halocarbons and Other Atmospheric Trace Gases Otto Instrument 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.

Automated flask sampling electron capture gas chromatograph ("Otto"): The Otto instrument has been in continuous use since late 1994 when the original Pre-Otto system was entering retirement. Since 1994, Otto has continued to analyze samples from the seven sites used by the Pre-Otto system. As of 2017, Otto's sampling network has expanded to include weekly air sampling at six additional sites including Summit Station, Greenland (SUM), Mace Head, Ireland (MHD), Park Falls, Wisconsin (LEF), Harvard Forest, Massachusetts (HFM), Cape Kumukahi, Hawaii (KUM), and Palmer Station, Antarctica (PSA). Sampling at Trinidad Head, California (THD), Grifton, North Carolina (ITN), and Ushuaia, Argentina (USH) has also come and gone during this period. The original three gases measured by GC-ECD since 1977 (N2O, CFC-12 and CFC-11) were extended to include CFC-113, CH3CCl3, CCl4 and SF6 when Otto came online.

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