China's Da Qi-1 satellite, carrying the Aerosol and Carbon Dioxide Lidar, produced column-averaged CO2 measurements that closely track NASA's OCO-2 and OCO-3 over selected regions, with daytime differences generally below 0.5 parts per million. The study covered June 2022 through December 2024 and used a unified framework to account for differences in sampling and vertical sensitivity between active lidar and passive sensors. The active instrument also matched ground-based TCCON sites with a mean bias of 0.21 ppm and an RMSE of 1.49 ppm. Because the laser does not rely on sunlight, DQ-1 kept valid monthly coverage in all 31 months across ten test regions, including Antarctica and the Boreal Forest where passive sensors often missed months. This makes DQ-1 a useful complement for tracking atmospheric CO2 trends, especially in cloudy, high latitude, or nighttime conditions.
