Global Monitoring Division

The Halocarbons and other Atmospheric Trace Species (HATS) group has been measuring CFC-12 since 1977. There have been four programs and dozens of instruments that have made measurements at many remote stations. Hemispheric and global means are calculated by assimilating measurements from the flask (12 stations) and in situ programs (6 stations). The CFC-12 data below is on the NOAA 2008 scale.

Click here for HATS CFC-12 data file

The figure below shows the different measurement programs' calculated global means. Flask measurements started in 1977 with six stations and continue today at 12 remote locations. The in situ program started in 1986 (called RITS) with a couple of gas chromatographs located at Mauna Loa, Hawaii and South Pole stations. The following few years instruments were added at Barrow, Alaska, American Samoa, and Niwot Ridge, Colorado. A four channel gas chromatograph was developed in 1998 (called CATS) and replaced the RITS in situ instrumentation. The CATS gas chromatographs are currently deployed at six field sites and make hourly measurements (hourly CATS measurements can be found here).

This combined CFC-12 data set is also used in NOAA's Annual Greenhouse Gas Index (AGGI) and NOAA's Ozone Depleting Gas Index (ODGI).

Follow the links below for data files from specific HATS monitoring programs or to see global comparison plots between differing measurement methods, click here.