Aeolus validation with the DLR airborne Doppler wind lidars: 2-µm heterodyne detection and 355 nm ALADIN Demonstrator

In the three years after the launch of ESA's wind lidar mission Aeolus in 2018, DLR conducted four airborne campaigns to validate its wind products. The DLR Falcon aircraft was equipped with two Doppler wind lidar (DWL) instruments, the ALADIN Airborne Demonstrator (A2D), the prototype of the Aeolus instrument, and a scanning heterodyne detection 2-µm DWL as a reference system. These instruments were operated concurrently for over 26,000 km along the Aeolus measurement track. Complementary and synergistic observations from both DWLs were used to characterize systematic and random wind errors of the Aeolus products, and to recommend algorithm improvements. Recently, the data obtained from campaigns in Iceland (2019) and Cape Verde (2021) was applied to validate reprocessed Aeolus wind products (Baseline 16). This paper provides an overview of the airborne validation campaigns and ongoing contributions to the Aeolus performance validation and processor evolution.