An improved CO2 retrieval method by combined observation of 532 nm Mie LiDAR and 1572 nm differential absorption LiDAR

Carbon dioxide is considered as the main factor leading to global climate change[1, 3]. Precise measurements, especially the different absorption lidar (DIAL), are needed for analyzing the carbon sources and sinks. The Ground-based DIAL usually emits on-line and offline lasers alternately[5, 8, 9], but aerosols fluctuations will affect the lidar signals. In order to offset the effects caused by aerosols fluctuations, a combined observation of 532 nm Mie lidar and 1572 nm DIAL was introduced and analyzed firstly. This paper analyzes the linear relation of the extinction coefficient between 532 nm lidar and 1572 nm lidar, and applies this connection to DIAL CO₂ retrieval by using an improved DIAL method, considering the importance of aerosols. The results obtained by 532 nm Mie lidar work as a reference, revealing an appropriate period of calculation and serving as calibration data. The result s of the combined observation show the feasibility of our experiment and method.