Comparison of optical-feedback cavity-enhanced absorption spectroscopy and gas chromatography for ground-based and airborne measurements of atmospheric CO concentration

摘要

We present the first comparison of carbon monoxide (CO)measurements performed with a portable laser spectrometer that exploits theoptical-feedback cavity-enhanced absorption spectroscopy (OF-CEAS)technique, against a high-performance automated gas chromatograph (GC) witha mercuric oxide reduction gas detector (RGD). First, measurements of atmospheric COmole fraction were continuously collected in a Paris (France) suburb over1 week. Both instruments showed an excellent agreement within typically 2 ppb(part per billion in volume), fulfilling the World Meteorological Organization(WMO) recommendation for CO inter-laboratory comparison. The compact size androbustness of the OF-CEAS instrument allowed its operation aboard a smallaircraft employed for routine tropospheric air analysis over the FrenchOrléans forest area. Direct OF-CEAS real-time CO measurements intropospheric air were then compared with later analysis of flask samples bythe gas chromatograph. Again, a very good agreement was observed. This workestablishes that the OF-CEAS laser spectrometer can run unattended at a veryhigh level of sensitivity (   1 ppb) and stability without any periodiccalibration.