An airborne instrument for fast-response, high-precision measurement of tro
pospheric carbon monoxide (CO) was developed using a vacuum ultraviolet (VU
V) resonance fluorescence technique. The excitation radiation is obtained b
y a DC discharge CO resonance lamp combined with an optical filter for the
CO fourth positive band emission around 150 run. The optical filter consist
s of a VUV monochromator and a crystalline quartz window (< 147-nm cutoff).
The crystalline quartz window ensures a sharp: discrimination against wave
lengths below 135.7 nm that yield a positive interference from water vapor.
Laboratory tests showed that the optical system achieved a precision of 1.
1 parts per billion by volume (ppbv) at a CO concentration of 100 ppbv for
a 1-s integration period, and the flow system provided a response time (Ile
time constant) of similar to2 s. The aircraft measurement campaign Biomass
Burning and Lightning Experiment-phase B (BIBLE-B) was conducted between A
ugust and September 1999 over the western Pacific and Australia. The flight
data obtained during this campaign were used to demonstrate the high preci
sion and fast response of the instrument. An intercomparison of the VUV CO
measurement and a gas chromatographic CO measurement was conducted during B
IBLE-B. Overall, these two independent measurements showed good agreement,
within the experimental uncertainties.