Balloonborne in situ gas chromatograph for measurements in the troposphere and stratosphere

Abstract

An in situ gas chromatograph (GC) instrument on a balloonborne package is described in detail and data from seven science deployments are presented. This instrument, the Lightweight Airborne Chromatograph Experiment (LACE), operates on the Observations of the Middle Stratosphere (OMS) in situ gondola and has taken data from the upper troposphere to near 32 km with a vertical resolution of better than 300 m. LACE chromatography has been developed to measure halon‐1211, the chlorofluorocarbons (CFC‐11, CFC‐113, CFC‐12), nitrous oxide (N 2 O), and sulfur hexafluoride (SF 6 ) every 70 s and methyl chloroform (CH 3 CCl 3 ), carbon tetrachloride (CCl 4 ), hydrogen (H 2 ), methane (CH 4 ), and carbon monoxide (CO) every 140 s. In the introduction we present scientific motivation for choosing this suite of molecules and for the use of faster sample rates resulting in unprecedented vertical resolution from an in situ GC. Results from an intercomparison with the Airborne Chromatograph for Atmospheric Trace Species (ACATS‐IV) instrument are shown to quantitatively connect this LACE data set to the complementary data set generated on board the NASA ER‐2 aircraft.