An Airborne 2-μm Double-Pulsed Direct-Detection Lidar Instrument for Atmospheric CO2 Column Measurements

Abstract

AbstractThis study reports airborne measurements of atmospheric CO2 column density using a 2-μm double-pulsed integrated path differential absorption (IPDA) lidar. This new 2-μm IPDA lidar offers an alternative approach to measure CO2 column density with unique features. The online frequencies of this lidar can be tuned to 1–6 GHz from the CO2 R30 absorption line peak. It provides high measurement sensitivity to the lower-tropospheric CO2 near the ground surface. This instrument was flown in the spring of 2014 in a NASA B200 aircraft. The results of these test flights clearly demonstrate the measurement capabilities of this lidar instrument. The CO2 column dry mixing ratio is compared to an in situ CO2 measurement by a collocated NOAA flight. The IPDA lidar measurement is determined to be in good agreement with a 0.36% difference, which corresponds to 1.48 ppm. It is the average difference between the IPDA lidar measurements and the NOAA air samples in the flight altitudes from 3 to 6.1 km.