Airborne measurements of the partial column-averaged dry-air mixing ratio of CO2 (XCO2) and moderate airplane height detection were performed using an amplitude-modulated 1.57-μm differential laser absorption spectrometer (LAS). The LAS system proved to be compact, reliable, and rigid in the field measurements. Airborne demonstration flights resulted in a high correlation coefficient of 0.987 between XCO2 observed from LAS and XCO2 calculated from in situ measurements. The average XCO2 obtained from LAS and in situ data agreed within 1.5 ppm, and the method achieved a measurement precision of 2.5 ppm for spiral measurements.
