The calibration and validation of XCO2 measured by Lidar onboard DQ-1

Atmospheric carbon dioxide (CO2) is the primary anthropogenic driver of climate change, accounting for more than half of the total effective radiative forcing (ERF). The accurate monitoring of carbon dioxide is essential to study the global carbon cycle and radiation budget on Earth.The Aerosol and Carbon Detection Lidar (ACDL) instrument, as the first space-borne integrated path differential absorption (IPDA) light detection and ranging (Lidar) for XCO2, was successfully launched in April 2022 onboard the DaQi-1 (DQ-1) satellite.During the two years of on-orbit operation, we constantly updated the processing methods, including the spectral broadening of CO2 caused by water vapor, etc. Finally, we calibrated and validated  the CO2 retrieved by DQ-1 usingTCCON and COCOON, and the results showed that the deviation reached the satellite design demand (1ppm).