Retrieval improvements for the ALADIN Airborne Demonstrator in support of the Aeolus wind product validation

Abstract. The realization of the European Space Agency's Aeolus mission was supported by long-standing development and field deployment Atmospheric LAser Doppler INstrument (ALADIN) Airborne Demonstrator (A2D) which, since launch satellite in 2018, has been serving as a key instrument for validation ALADIN, first-ever wind lidar (DWL) space. However, capabilities A2D are compromised deficiencies dual-channel receiver like its spaceborne counterpart, consists Rayleigh complementary Mie spectrometer sensing speed from both molecular particulate backscatter signals, respectively. Whereas accuracy precision channel is limited spectrometer's high alignment sensitivity, especially near instrument, large systematic errors caused aberrations interferometer combination with temporal overlap adjacent range gates during signal readout. two error sources mitigated modifications retrieval algorithm. A novel quality control scheme implemented, which ensures that only return signals within small angular further processed. Moreover, results bias opposing sign bins vertically averaged. resulting improvement performance evaluated context airborne campaigns were conducted between May September 2019. Comparison data against high-accuracy, coherent DWL deployed parallel on board same aircraft shows refinements considerably decrease random line-of-sight (LOS) winds about 2.0 to 1.5 m s?1, demonstrating capability such direct detection DWL. Furthermore, measurement could be largely extended up 2 km instrument's close aircraft. below 0.5 s?1 (LOS), hence allowing an accurate assessment campaign. latter revealed different biases Level 2B (L2B) Rayleigh-clear Mie-cloudy horizontal LOS (HLOS) ascending descending orbits, well 3 6 winds, In addition evaluation, present study discusses applicability developed algorithm processor, thereby offering prospects improving quality.