Disclaimer: This material is being kept online for historical purposes. Though accurate at the time of publication, it is no longer being updated. The page may contain broken links or outdated information, and parts may not function in current web browsers. Visit espo.nasa.gov for information about our current projects.

 

Airborne Chromatograph For Atmospheric Trace Species (ACATS)

Status

Operated By: 
PI
Replaced By: 

Megan Northway, John Holecek, Pavel Romashkin, Dale Hurst, Steve Ciciora

ACATS-IV is a 4-channel gas chromatograph with electron capture detection (ECD) that measures a variety of halocarbons and other long-lived trace gases in the stratosphere. The instrument is currently configured to measure CFC-11 (CCl3F), CFC-12 (CCl2F2), CFC-113 (CCl2FCClF2), methyl chloroform (CH3CCl3), carbon tetrachloride (CCl4), halon-1211 (CBrClF2), chloroform (CHCl3), methane (CH4), and hydrogen (H2) every 125 s, and nitrous oxide (N2O) and sulfur hexafluoride (SF6) every 250 s. Each channel is comprised of a sample loop (2-10 cm3 volume), gas sampling valve (GSV), chromatographic column pair, ECD, electrometer, and several flow, temperature, and pressure controllers. In-flight calibration is carried out every 625 s (1250 s for N2O and SF6) by injecting a dried, whole air standard containing approximately 80% of tropospheric mixing ratios.

Instrument Type: 
Aircraft: 
Point(s) of Contact: 
James W. Elkins (POC; PI), Eric Hintsa (Co-I), Fred Moore (Co-I)