The CATS instruments
have been in continuous operation at the NOAA baseline
observatories since 1999. While the CATS instruments
measure the same compounds as their predecessor, the Radiatively
Important Trace Species (RITS) instruments; these gas chromatographs
(GCs) also measure several additional trace gases including
carbonyl sulfide (COS), halon-1211 (CBrClF2),
HCFC-22 (CHClF2), HCFC-142b (CH3CClF2)
and methyl chloride (CH3Cl). The CATS GCs are
custom built instruments with four separate channels. Each
channel is comprised of a pair of separation columns, flow
controllers, an air selection valve, and an electron capture
detector. More information on the ESRL/GMD in situ programs
and chromatography techniques can be found here.
