The HATS flask GC-MSD program measures CF4 with the PERSEUS instrument.
Atmospheric dry mole fractions (parts-per-trillion or ppt) of CF4 measured by GC-MSD in the HATS flask program. Each point represents a monthly mean at one of 8-12 stations: Alert, Canada (ALT), Summit Greenland (SUM), Barrow, Alaska (BRW), Mace Head, Ireland (MHD), Trinidad Head, California (THD), Niwot Ridge, Colorado (NWR), Cape Kumukahi, Hawaii (KUM), Manua Loa, Hawaii (MLO), American Samoa (SMO), Cape Grim, Australia (CGO), Palmer Station, Antarctica (PSA), South Pole, Antarctica (SPO).
Zonal mean dry mole fractions (ppt) are estimated by equally weighting monthly mean measurements in each latitude band. Small gaps (less than 6 months) are interpolated prior to averaging. Large data outliers are filtered (>3 sigma). Solid lines are used for Northern hemispheric measurements and dashed for the Southern hemisphere.