Attenuated atmospheric backscatter profiles measured by the CO<sub>2</sub> Sounder lidar in the 2017 ASCENDS/ABoVE airborne campaign

Abstract. A series of attenuated atmospheric backscatter profiles were measured at 1572 nm by the CO2 Sounder lidar during the eight flights of the 2017 ASCENDS/ABoVE (Active Sensing of CO2 Emission over Nights, Days, & Seasons mission, Arctic Boreal Vulnerability Experiment) airborne campaign. In addition to measuring the column average CO2 mixing ratio from the signals reflected by the ground, the CO2 Sounder lidar also recorded the height-resolved attenuated atmospheric backscatter profiles beneath the aircraft. We have recently processed these vertical profiles with a 15-m vertical spacing and 1-s integration time along the flight path (~200 m) for all the 2017 flights and have posted the results at NASA Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC) for Biogeochemical Dynamics (Sun et al., 2022), https://doi.org/10.3334/ORNLDAAC/2051. This paper describes the principle of these lidar backscatter profile measurements, their data processing, and estimated signal to noise ratio.