Abstract. We present the development and assessment of a new flight system that uses a
commercially available continuous-wave, tunable infrared laser direct
absorption spectrometer to measure N2O, CO2, CO, and
H2O. When the commercial system is operated in an off-the-shelf
manner, we find a clear cabin pressure–altitude dependency for
N2O, CO2, and CO. The characteristics of this artifact
make it difficult to reconcile with conventional calibration methods. We
present a novel procedure that extends upon traditional calibration
approaches in a high-flow system with high-frequency, short-duration sampling
of a known calibration gas of near-ambient concentration. This approach
corrects for cabin pressure dependency as well as other sources of drift in
the analyzer while maintaining a ∼90 % duty cycle for 1 Hz sampling.
Assessment and validation of the flight system with both extensive in-flight
calibrations and comparisons with other flight-proven sensors demonstrate the
validity of this method. In-flight 1σ precision is estimated at
0.05 ppb, 0.10 ppm, 1.00 ppb, and 10 ppm for N2O,
CO2, CO, and H2O respectively, and traceability to World
Meteorological Organization (WMO) standards (1σ) is 0.28 ppb,
0.33 ppm, and 1.92 ppb for N2O, CO2, and CO. We show
the system is capable of precise, accurate 1 Hz airborne observations of
N2O, CO2, CO, and H2O and highlight flight
data, illustrating the value of this analyzer for studying N2O
emissions on ∼100 km spatial scales.
A compensation method for the consistency of multi-channel mixing circuit for solar radio observation system